EDC Pen Buying Guide - 28 of the Best | WornSimple.com
EDCPens

EDC Pen Buying Guide – 28 of the Best

By December 7, 2020 No Comments
EDC Pen Buying Guide - 28 of the Best

Are pens, especially those that can serve as a vital tool of your EDC (everyday carry) gear, a bulwark against the soundbites and increasingly shorter attention spans of our social media addled brains? To say that we live in a fast-paced world is an obvious cliche. And yet, we live in a society where technology threatens to replace countless traditional ways of doing things. One small yet mighty item that competes with these modern changes is the good old pen. While we’ve already covered the best tactical pens, today, we’re going to explore the EDC pen landscape.

Best Choice
Budget Choice
Premium Choice

Despite incredible advances like the Apple Pen in simulating the feel of writing and drawing, there is still no laptop, tablet, or smartphone capable of replacing the thrill of writing with a real pen. And if you happen to find the right writing instrument that you can carry with you anywhere and put it to paper, the experience can still be pure bliss. It can help organize your thoughts and even slow your mind to a state of deep contemplation and introspection. That’s something we all need a little bit more of these days. Thinking. What a concept!

The almighty EDC pen can help capture your ideas and concepts, sketches, and scribbles anytime, anywhere. You don’t need any software to rely on, just a pen, paper, and your creativity.

In this quick guide, I look at the various ballpoints, fountains, rollerballs, gel, and other novelty pens ideal for everyday use. These pens vary in terms of the barrel material, cartridge, tip, grip, and technology. These are machined pens in vibrant colours delivering smooth and long-lasting writing. Their stainless steel, brass, titanium, copper, or aluminum barrels can withstand extreme temperatures and harsh handling. Indeed, these are the attributes we want in what I consider to be the best EDC pens.

1. The Classic Machined Pen

The Classic Machined Pen from Schon DSGN is a lightweight, compact titanium EDC pen. It retails in polished aluminum, black anodized aluminum, tumbled stainless steel, polished brass, night sky, and Liza Frunk Revival finishes. These variations differ in terms of weight and feel, with the polished copper as the heaviest. This pen has a solid grip and smooth flowing ink. It will complement anyone working in the medical field, sports, or retail. Use it for those distinct signatures, sketches, or taking notes.

Key Features

  • Classic titanium EDC pen with a touch of sophistication
  • Retails in 9 versatile metal finishes
  • Uses replaceable cartridges, colourful, fine gel, and D1 in

Specifications

  • Brand: Schondsgn
  • Models: Polished Aluminum Pen- 1oz – 1.1oz (w/clip), Black Anodized Aluminum – 1oz 1.1oz (w/clip), Polished Titanium -1.8oz – 1.9oz (w/clip), Tumbled Stainless – 2.8oz – 2.9oz (w/clip), Polished Brass Pen – 3 oz -3.1oz (w/clip), Polished Copper – 3.2oz -3.3oz (w/clip)
  • Dimensions: Diameter – 0.5″, 4″ long when capped

2. Zebra F-xMD Ballpoint 1.0mm Silver 24380

The Zebra F-xMD Ballpoint 1.0mm Silver 24380 is an executive-style stainless steel pen, replacing the previous F-701 model. Unlike its predecessor, this model features an all-metal clicker and 0.7mm refillers. This improvement means that your stainless steel barrel has all its components detectable on an x-ray. That way, it is suitable for anyone working in a production line or high-temperature environments and getting through a TSA line. Besides, its knurled grip guarantees to produce your best handwriting on paper.

Key Features

  • Black, stainless steel EDC pen
  • Replacement of the F-701 series that is no longer in production
  • Includes a non-slip diamond cut for perfect grip
  • Convenient glide ink style

Specifications

  • Brand: Zebra Pens
  • Dimensions: 5.2 x 0.51 x 0.31 inches; 0.64 ounces
  • Ink Colour: Black
  • Materials: Stainless Steel and Brass

3. Fisher Space Pen Raw Brass Bullet Pen (400-RAW)

The Fisher Space Pen uses a pressurized ink cartridge to operate in conditions similar to space. For example, you can use this pen to write at any angle, defying any pull of gravity. Plus, the ink flow and performance remain unaffected in extreme temperatures between -30F and 250F. That aside, this bullet pen uses an attractive raw unfinished brass casing that reflects the current environment and how you hold and handle it.

Key Features

  • An all brass stylish bullet pen
  • Retails as 1-pack or 2-pack
  • Retails with an unconditional lifetime guarantee

Specifications

  • Brand: Fisher Space Pen
  • Dimensions: Diameter – 0.3″, 5.3″ long when capped
  • Colour: Raw Brass
  • Material: Brass

4. Machine Era Pen | Original Brass

This awesome writing tool is a brass EDC pen with a golden brown luxurious shine. It uses a Pilot G2 cartridge with an extra-fine point that guarantees exceptional writing. Further, this pen has no rubber O-rings, hence, minimizing wear and tear. Plus, its cap attaches at the back of the body when writing. Use this pen to stand out as you jot down action points in a brainstorming round table or capture some sketches for a future presentation.

Key Features

  • Compact brass EDC pen with an attractive aged appearance
  • Balanced weight for a comfortable hand grip
  • Retails in various colours and weights

Specifications

  • Brand: Machine Era
  • Dimensions: Diameter – 0.4″, 4.6″ long when capped; 1.6 oz
  • Colour: Original Brass

5. Metal Trekker Pen

Do you need to record your observations while working under extreme conditions? The Metal Trekker Pen is reliable when on a wet, greasy, sweaty, or muddy surface. Its pressurized ink delivers continuous writing in temperatures of between -30F to 250F and underwater up to 35 feet. Besides, it retails with a convenient key-ring cap to attach it to your other gear or backpack.

Key Features

  • All-weather pen ideal in extreme wet conditions
  • Includes a 0.9mm cartridge refill for black ink
  • Uses a rubber grip for a secure feel

Specifications

  • Brand: Rite in the Rain
  • Dimensions: 4.5″ with cap, 3.625″ without, barrel diameter .375″
  • Weight: 0.05 lbs
  • Colour: Flat Black

6. Investigator Spiral Pen- Titanium Stonewash Bronze

The Investigator Spiral Pen is an EDC pen with a titanium stonewash finish. This pen relies on the CNC and CAD_ CAM technology for an efficient, light ink delivery. It’s Titanium tough construction ensures that this pen’s barrel remains smooth and long-lasting despite any harsh treatment throughout its lifespan. In turn, you can rely on the pen’s Fisher Space Pen full-size pressurized refills to write in wet conditions, including underwater.

Key Features

  • Comfortable weight and deep grooves for a solid grip
  • Can withstand extreme working conditions

Specifications

  • Brand: Rick Hinderer
  • Dimensions: 3/8″ Diameter – Overall Length 4 ¼”
  • Material: Titanium
  • Weight: 0.2 Oz

7. Grafton Pen

Shopping for a high-quality pen can be a trying experience. There are so many to choose from! That’s why most consumers prefer getting buy-it-for-life EDC pens, so they never have to think about picking an awesome writing instrument again. If that’s the kind of pen you’re looking for, consider the Grafton Pen, a heavy-duty yet balanced product that sells for a competitive price.

This pen is made from a pure aluminum barrel with a heavy-duty bolt-on clip. This clip advances and retracts the refill in advance for convenient use. It is the type of barrel that you buy for life, quite literally. This pen uses the latest high-performance Grafton refill compatible with other durable pens like Bic Gel, Fisher Space Pen, Parker Gel, Uniball Jetstream, and Monteverde Ballpoint refill cartridges.

Key Features

  • Almost indestructible, aluminum EDC pen with a bolt-on clip
  • Balanced weight and deep grooves for a comfortable grip
  • Waterproof, ideal for travel

Specifications

  • Brand: Everyman
  • Dimensions: Diameter 11mm, Length 145mm, 1 oz
  • Material: 100% Anodized 6061 Aluminum

8. PicoPen

The PicoPen is a stylish, small, and functional EDC pen retailing in either aluminum bronze or stainless steel finish. It is the type of finish that oxidizes over time, giving the pen barrels an appealing aged appearance as they age. This pen measures only 3.25 inches long and weighs a mere 0.5 oz, a lightweight and compact size fitting your keychain or tiny drawer. It uses a readily available D1 style ink refill for your convenient replacement. This refill is compatible with Fisher pressurized refills, giving you a versatile choice of colour and feel. The barrel has a magnetic cap that attaches easily to your backpack, keychain, belt loop, or golf bag.

Key Features

  • Robust stainless steel or aluminum bronze EDC pen
  • Includes a convenient 12mm split ring and snap ring
  • Ink refill compatible with Fisher pressurized refills (SU1F, SU2F, SU4F)
  • Has a 90-days warranty

Specifications

  • Brand: TEC Accessories
  • Dimensions: 3-1/4″ [82.5mm] long (including cap), 0.23″ [6.0mm] in diameter
  • Material: Stainless Steel, Aluminum Bronze

9. Zebra Pen 29411 F-701 Ballpoint Stainless Steel Retractable Pen

If you prefer a stainless steel top EDC pen, then consider getting the Zebra Pen 2941. This pen features a designer stainless steel barrel, clip, and tip with a sleek yet rugged look. This EDC pen uses its fine point and silent retractable plunger to glide the ink over any surface for well-defined writing performance. And, there is a knurled up metal grip that stabilizes your hand as you write.

Key Features

  • Stainless steel retractable ballpoint pen
  • Knurled metal grip for stability
  • A durable 0.8mm Zebra’s F-Refill (85512) cartridge
  • Designer metal clip
  • Silent retraction plunger

Specifications

  • Brand: Zebra Pen
  • Dimensions: 1 x 3.3 x 8 inches; 0.32 Ounces
  • Colour: Black, Stainless Steel
  • Material: Stainless Steel

10. Zebra Sharbo X TS10 Premium Aluminum Pen

If you have a young one or a student, consider getting them the Zebra Sharbo X TS10 Premium Aluminum Pen for their everyday use. This Japanese-imported EDC pen has a well-balanced aluminum barrel in graphite black, blue, navy gold, black gold, and brown gold finishes. The blue and navy gold barrels use a rotary system that includes a ballpoint pen and a mechanical pencil. The small hints of gold plating add some distinctive features, making it suitable for the office and those fancy meetings as well.

Key Features

  • Well-made aluminum EDC pen
  • Retails in 5 versatile finishes
  • Made in Japan

Specifications

  • Brand: Zebra
  • Dimensions: 19 x 7.6 x 4.7 centimeters
  • Material: Aluminum

11. Rite in the Rain Weatherproof Black Metal Clicker Pen

The all-weather metal pen from Rite in the Rain delivers continuous writing in wet and cold conditions. Further, it uses a pressurized ink cartridge that remains effective in extreme temperatures between 30F and 250F. You can use the pen in an upside position without worrying about the ink leaking out, evaporating, or blowing up in harsh conditions.

Key Features

  • A classic Cap-O-Matic all-metal pen
  • Has an all-weather texturized tip
  • Uses all-weather blue and black ink
  • Available in Flat Black, Safety Blaze Orange, Flat Dark Earth, Olive Drab finishes

Specifications

  • Brand: Rite in the Rain
  • Dimensions: Length 5 1/4″, diameter of 3/8″
  • Material: Metal Barrel

12. Gerber Impromptu Tactical Pen, Black

Are you in the military or law enforcement? Perhaps you’re an international spy? This Archer (the TV show, look it up) approved tactical pen has plenty of features to love, not the least of which that it’s got a superb and rugged finish. This EDC tactical pen features a rugged stainless steel barrel and pocket clip. It relies on the Rite in the Rain pressurized ink cartridge to deliver smooth flowing ink regardless of the conditions. Of course, it can also be used to break a windshield or defend yourself from an unexpected attack. It’s your ultimate writing companion.

Key Features

  • Tempered steel tactical pen ideal for everyday use
  • Deploys via a push button
  • Has an integrated glass-breaker tip for emergencies

Specifications

  • Brand: Gerber
  • Dimensions: 1.27 x 13.97 x 24.13 cm; 63.5 Grams
  • Colour: Black
  • Material: Stainless Steel

13. Tactile Turn - Titanium Click Pen

The Titanium Click Pen is an all-titanium click pen retailing in standard and short length versions. The barrel relies on the tough PVD and DLC coatings for its incredible lustre. Further, it uses a unique click mechanism that is silent and effective for years. So don’t worry, with this pen, you’ll never get any accidental pocket stains.

Key Features

  • Titanium EDC pen with a unique click mechanism
  • Stainless steel clip
  • Retails in 4 versatile finishes
  • Engraving available on request

Specifications

  • Brand: Tactile Turn
  • Dimensions: Standard Length 5.5”,1.2oz; Short Length 5.0”, 1.1oz; Diameter 0.43”
  • Material: Titanium

14. Zirconium Bolt Action Short Pen

The Zirconium Bolt Action Short Pen is a truly premium EDC pen. What makes it so special? Naturally, the answer is in the name of the product. It uses the rare metal known as Zirconium for its barrel. What’s awesome about Zirconium? It’s essentially resistant to all forms of corrosion, and it’s also astonishingly strong. That’s part of the reason why it’s often used in the construction of surgical instruments. This construction creates a rugged, dependable, and easy to use bolt action pen. The pen’s cartridge is compatible with all Parker style refills, hence convenient for everyday use for a lifetime.

Key Features

  • Use the Schmidt Easy Flow 9000 cartridge
  • Distinct arcing bolt action clicker
  • Made in the USA

Specifications

  • Brand: Tactile Turn
  • Dimensions: 5.1″ L x 0.43″ D, 1.6 oz weight
  • Colour: Zirconium
  • Weight: 1.6 oz

15. The James Brand - The Benton EDC Pen

The Benton is a tough stainless steel writing instrument from the James Brand with all the bells and whistles you could reasonably expect from a compact EDC pen. It uses the high-performance Schmidt 900 refillable ink cartridge to deliver smooth writing while a twist-off enclosure, protects the ink cartridge. The lanyard loop makes it easy to stow and tough to lose. So go ahead, treat this pen like it’s the last one you’ll ever have to buy.

Key Features

  • Laser-etched grip pattern near the bottom of the barrel
  • Limited lifetime warranty
  • 304L Stainless steel barrel construction

Specifications

  • Brand: James Brand
  • Dimensions: Length: 5½”, Diameter: ⅜”
  • Colour: Black
  • Material: Stainless Steel

16. Shinola + Fisher Space Pen Clutch W/Lightning Bolt Logo

The Fisher’s Clutch Pen is a unique, almost futuristic looking, durable pen known to last up to three times as long as a regular ballpoint pen. It uses a black anodized aluminum barrel that is lightweight and nearly indestructible. Its hexagonal finger grip guarantees a solid grip while you while away your hours thinking up the next great idea. Or drawing silly faces, you know, one or the other.

Key Features

  • All-weather Fisher Space Pen cartridge
  • Balanced weight for flawless writing at any angle
  • Steady grip
  • Aesthetic lightning bolt logo

Specifications

  • Brand: Shinola Detroit
  • Dimensions: 5.45 x 0.52 x 0.52 inches
  • Weight: 1.41 ounces
  • Colour: Black

17. Pilot Vanishing Point Collection Retractable Fountain Pen

If you prefer an EDC fountain pen, opt for the Pilot Vanishing Point Collection Retractable Fountain Pen. It retails as an ingenious design courtesy of the radar-invisible technology. Hence, it is a large, durable, and attractive pen. Its matte black barrel coupled with the 18-karat gold rhodium-plated nib makes it suitable for those one-off signatures.

Key Features

  • An EDC retractable fountain pen
  • Retails in 14 versatile finishes
  • Come in an elegant gift box

Specifications

  • Brand: Pilot
  • Dimensions: 12.7 x 2.5 x 2.5 cm
  • Material: Plastic
  • Nib Type: Broad, Fine, Medium

18. Fisher Space Pen Men's Original Astronaut Space Pen

This EDC pen is THE original Fisher Space Pen used in the 1968 Apollo 7 space mission. It features an all brass and steel barrel built to last in space-like conditions. Plus, there is a retractable closure with a self-sealing tip to contain the volatile writing fluid. This style allows you to defy gravity and write at any angle you want. Hence, use this pen to master your fountain pen calligraphy. Also, this pen performs exceptionally in extreme temperatures of between -30F and 250F. 

And do you remember that old story about how NASA spent millions of dollars to develop this pen for use by their astronauts, while the Russians simply handed their cosmonauts pencils? Yeah, that’s just a myth, but it still makes for an interesting story about the development of this Fisher Space Pen. 

Key Features

  • Precision assembled and hand-tested to write well in extreme temperatures.
  • Hand washable
  • Includes an unconditional lifetime guarantee
  • Retails in the original packaging from the manufacturer

Specifications

  • Brand: Fisher Space Pen
  • Dimensions: Length 5.0”, Diameter 0.375″
  • Colour: Chrome

19. Montblanc - StarWalker Metal Ballpoint Pen

The StarWalker Metal Ballpoint Pen is a premium EDC pen retailing in a platinum-coated clip and barrel. It is the type of ballpoint pen you want to have when signing a marriage certificate or sealing a significant deal. The blue tip at the top of the pen, along with its stunning body, is what makes this more of a work of art than a pen. Nevertheless, it makes for a pretty swanky gift for anyone who likes nice writing tools and stationa

Key Features

  • Platinum-coated ballpoint pen
  • Has the Montblanc brand name and individual serial number
  • Compatible with most ballpoint refills
  • Free engraving upon request

Specifications

  • Brand: Montblanc
  • Dimensions: 134.5 x 13.1 mm; 57.88g
  • Colour: Silver

20. Fisher Space Telescoping Space Pen (TLP)

The Fisher Space Telescoping Space Pen (TLP) is a typical gravity-defying Fisher Space Pen, performing exceptionally in temperatures of between -30F to 250F. Further, the pen has a ribbed grip giving it its telescoping design. Its aluminum barrel with a retractable cartridge, medium point, and Tungsten Carbide Ball tip will last for a lifetime.

Key Features

  • Effective in extreme temperature conditions
  • Writes at any angle
  • Uses a comfortable ribbed grip

Specifications

  • Brand: Fisher Space Pen
  • Dimensions: 4.25 x 0.6 x 0.6 inches
  • Colour: Matte Silver
  • Nib Type: Medium

21. Ti Arto EDC: The Ultimate Refill Friendly Everyday Carry Pen

What challenges do you face when refilling your EDC pens? You can overcome them all when you make the bold and brave decision to get the Ti Arto EDC. Ok, maybe it’s not some gigantic leap of bravery and self-sacrifice, but for real, this is one of the most adjustable pens you will ever come across. It accepts up to 750 different refill cartridges, courtesy of its customizable solid titanium barrel. Hence, you now have an EDC pen to pass down your generations.

Key Features

  • Customizable titanium EDC pen
  • Compatible with up to 750 different refill cartridges
  • Has an anti-slip grip and a screw-on style cap
  • Retails with a lifetime warranty
  • Available in three colour finishes

Specifications

  • Brand: Bigidesign
  • Dimensions: 10 x 5 x 20 cm
  • Weight: 55 Grams
  • Color: Black
  • Nib Type: Medium

22. Tactile Turn - Bolt Action Pen

The Bolt Action Pen from Tactile Turn is a sleek, balanced EDC pen retailing in three sizes and four metal finishes. It features a lightweight, corrosion-resistant titanium body. Additionally, this pen is also available in an anti-microbial copper, eye-catching bronze, or the rare grey-white Zirconium. Each of these models has a perfectly engineered interior and exterior for an extra smooth writing experience. For example, each pen features a standard or titanium Damascus bolt. This bolt has several alloys that forge together, resulting in an attractive pattern.

Key Features

  • A well-machined bolt action pen for everyday use
  • Custom engravings available on request
  • Has a lifetime warranty

Specifications

  • Brand: Tactile Turn
  • Dimensions: Standard 5.6″ long, Short 5.1 inches long, Mini 4.4″ long
  • Material: Titanium, Copper, Bronze, Zirconium

23. Inventery - Mechanical Pen

The Mechanical Pen from Inventery is a silent all-metal clicker pen measuring 5-inches long. It has the Schmidt P8126 cap-free rollerball refill for smooth writing on most surfaces. Plus, its all-brass barrel is abrasion-resistant, maintaining its form despite any harsh handling.

Key Features

  • A silent all-brass clicker pen
  • Uses individualized serial numbers
  • Has a lifetime warranty

Specifications

  • Brand: Inventery
  • Dimensions: Length 5″, 2.22 oz
  • Colour: Black Oxide

24. The First Grovemade Pen

The First Grovemade Pen is a classic EDC desk pen in three elegant finishes. Guaranteed to last a lifetime, the three finishes have very distinct looks. The hand-polished brass for that aged appearance. The aluminum version with a ceramic coating results in a black matte finish, or the awesomely crafted Titanium version. All these variations have a well-balanced weight that feels just right when writing. Furthermore, the pens use the premium 0.6mm Schmidt P8126 rollerball inserts for smooth writing. According to Grovemade, this is the pen that your desk has been dreaming of.

Key Features

  • Available in titanium, brass, or black aluminum finish
  • Its three flattened surfaces prevent it from rolling off the desk.
  • Has an old school appeal with a modern twist
  • Retails with a convenient little wood stand in steel base

Specifications

  • Brand: Grovemade
  • Dimensions: 5.65” long, 0.41” diameter
  • Colour: Black

25. Boker Plus Tactical Pen Cid Cal .45, Gray

This is a pen with a twist. Standing at 5 inches long, the Boker Plus Tactical Pen Cid Cal .45, Gray comes in handy in self-defence situations and serves as your EDC pen on regular non-dangerous days. Made of an indestructible hard coat anodized aluminum barrel, this EDC pen features a flat head, and uses a bolt action mechanism. It includes a plain edge stainless steel blade essential in self-defence circumstances. Hence, it is an ideal pen for anyone in law enforcement, military, or emergency operations.

Key Features

  • A well-made tactical pen that is ideal for EDC use
  • Comfortable grip, smooth writing
  • Uses a twist closure type

Specifications

  • Brand: Boker Plus
  • Dimensions: 12.7 x 2.54 x 2.54 cm; 45.36 Grams
  • Colour: Grey Aluminum

26. Limited Edition multi-colour Classic Ballpoint Pens

The Limited Edition Multi-Color Classic Ballpoint Pens are multicoloured aluminum EDC Pens weighing between 1oz and 1.1oz (w/clip). This lightweight yet compact style ensures you have a steady grip when taking notes or making sketches. Plus, it uses the PR4 Medium Black Fisher Space pen ink cartridge, which is readily available in the US.

Key Features

  • Multicolour aluminum EDC pens in
  • Retails in 9 versatile metal finishes
  • Replaceable cartridge readily available

Specifications

  • Brand: Schondsgn
  • Dimensions: Diameter – 0.5″, 4″ long when capped
  • Colour: Multicolour

27. Fisher Space Pen Side Release Button Ballpoint Retractable Pen

The Fisher Space Pen AG7 – BTN is a variation of the original Astronaut Space Pen, constructed out of an all-black titanium nitride barrel. This sleek yet durable finish enhances the pen’s resistance against abrasion. Still, it maintains all the other aspects of the original barrel. That includes the length, weight, distinct clicking mechanism, and a side button to retract the point. Each component is hand-tested and precision assembled to confirm its suitability in space-like conditions. Hence, you can write with the pen at any convenient angle.

Key Features

  • An Astronaut Space Pen variation in Black Titanium Nitride finish
  • Uses the Fisher PR4 Black Ink Medium Point cartridge
  • Performs exceptionally in extreme temperatures of between -30F and 250F
  • Includes a gift box with an astronaut sleeve

Specifications

  • Brand: Fisher Space Men
  • Dimensions: Length 5.0″, Diameter 0.375″
  • Colour: Black Titanium Nitride

28. Faber-Castell E-Motion Fntn Pen Pure Black

What is your go-to black pen for everyday writing? If you’re looking for a high-end, premium EDC pen that delivers a smooth flow, and uses the best performing ink cartridge, do not pass “GO,” do not collect $200; simply have a look at this amazing pen. This attractive pen comprises a 5.4-inch long black anodized aluminum barrel, a black cap and clip, and a medium tip.

Key Features

  • A deep black EDC pen with diamond engraving
  • Comfortable weight for a solid grip
  • Uses an attractive chrome-plated black cap and clip
  • Smooth flowing ink

Specifications

  • Brand: Faber Castell
  • Dimensions: 10 x 5 x 20 cm; 55 Grams
  • Color: Black
  • Nib Type: Medium

Conclusion

The best EDC pens are dependable, abrasion-resistant, and perform well in nearly every condition. The above 28 of the best EDC pens meet and surpass many of these criteria for excellence in writing instruments. Plus, they make the perfect gift for a loved one. So pick your choice, engrave it, customize the barrel to your preferred cartridge, or test it against gravity. Whatever your style, these choice everyday carry pens will deliver.