


OTTER Mercator Pocket Knife
Description
The Otter Mercator is a German lockback pocket knife with a 3.25" blade and a slim black steel handle, finished with a bail and a pocket clip. It comes in two versions: a traditional carbon steel blade or a satin-finish stainless steel blade. Both are made in Solingen, Germany, the city that has been the center of German knifemaking for centuries, and the design has barely changed since the 1860s.
Short and Sweet
- OTTER-Messer Mercator lockback with clip
- 4.25" (10.8 cm) closed with a 3.25" (8.26 cm) blade
- Blade options: carbon steel (OTT10436) or satin-finish stainless steel (OTT10436R)
- Nail nick opening
- One-piece folded steel handle with black finish
- Lockback with bail and steel pocket clip
- Made in Solingen, Germany
- Condition: New
The Mercator: Solingen, 1867
Heinrich Kaufmann & Söhne developed the Mercator knife in Solingen in 1867. Its best-known model, the K55K, takes its name from Kaufmann, the company's address at Hochstraße 55, and Katze, the German word for the cat logo stamped on the handle. The knife wasn't designed for the military, but German soldiers took to it early on, and some called it the "Kaiser Wilhelm knife." After World War II, American GIs brought Mercators home, where they became known as "Black Cat" knives and earned a loyal following. OTTER-Messer, a Solingen cutler founded in 1840, took over Mercator production in 1995 and still builds the knife to the original pattern.
Folded Steel, Two Blade Choices
The handle is a single sheet of steel folded into a channel, which makes the knife thin, light, and very hard to break. A back spring locks the blade open, and a steel pocket clip and bail give you two ways to carry it. You open the blade with the nail nick, the traditional way. The carbon steel version takes a very sharp edge, sharpens quickly on a stone, and develops a gray patina with use, so wipe it dry and add a drop of oil now and then. The stainless steel version trades a little of that easy sharpening for strong rust resistance and needs almost no upkeep.
Everyday Carry the Old Way
The Mercator's thin profile disappears in a front pocket, which is why tradesmen, farmers, and anglers have carried it for generations. Owners use theirs for cutting cord, opening feed sacks and boxes, cleaning fish, and slicing apples or sausage on the trail. Choose stainless if your knife will see saltwater, fish slime, or food prep, or if you want a carry knife you can forget about. Choose carbon if you like a traditional blade that you sharpen yourself and that shows its history over time.
Pairs well with
Curious About Sizing?
Given the massive variety of clothing we carry, a standard sizing guide is incredibly helpful for customers seeking the best fit.
Please understand that surplus varies widely in fit and cut and this sizing chart is general advice rather than tailor-level fitting.
Nearly every military has different sizing charts and schemes, which is why we've taken the time to put together this brief tutorial.
Jacket & Shirt Sizing
In absence of an established military size chart, we measure each jacket or shirt from armpit to armpit to get a rough idea of how it fits. If a garment is between sizes, we mark it one size down. For example, if a shirt measures 19.75" from pit to pit, it is marked as a small rather than medium.
To measure pit to pit, close up your shirt or jacket and measure from armpit to armpit.
This is our measurement guide that we use to measure garments without an existing military size chart:
14"-15" PtP = XXS
16-17" PtP = Extra Small
18"-19" PtP = Small
20-21" PtP = Medium
22-23" PtP = Large
24-25" PtP = Extra Large
26-27" PtP = XXL
28-29" PtP = 3XL
Pant Sizing
We typically convert pants to US waist and inseam sizes. If a pair of pants is between sizes, we mark it one size down. For example, if a pair of pants measures as a 33 waist, it is marked as a 32 waist.
To take these measurements we lay a pair of pants flat on the ground. We then measure across the waist and double the measurement. For example, if a pair of pants measures 16" across the waist it will fit a US 32 waist.
To determine inseam we measure from the crotch seam to the bottom of the cuff. For example, it a pair of pants measures 30" from the crotch seam to the bottom of the cuff we will list it as a 30 inseam or 30L.
Surplus Condition Guide
- Unissued
- These items are brand new. They may sometimes exhibit signs of storage. They may be new in their original factory packaging, but most times will not be.
- Issued; Good / Issued
- These items are in issued/used condition but are fully functional. This grade of surplus item may also exhibit signs of use such as stampings, small stains or general dirtiness.
- Issued items will not have missing or broken buttons, zippers or be missing any functional components unless noted as such in the product description. Any items you purchase that are marked as "Issued; Good" but exhibit these defects will be replaced free of charge by Americana Pipedream.
- Grade 2
- These items are in issued/used condition but have defects that impede function. This may include missing buttons, broken zippers, holes and tears. They may also be missing components.
- This is the lowest grade of surplus item that we carry and they are not eligible for returns or exchanges due to condition.
Prop 65 Warning
All products that are NOT INTENDED FOR CONSUMPTION OR NOT FOOD PRODUCTS fall under this warning:
“WARNING: This product contains a chemical known to the State of California to cause cancer.” WARNING: This product can expose you to chemicals including arsenic, which is known to the State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov.”
In stock! Ships within 3-5 business days, or we'll refund your shipping cost.
First-class customer service, guaranteed.
Free exchanges & returns.

OTTER Mercator Pocket Knife
If you have any questions, you are always welcome to contact us. We'll get back to you as soon as possible, within 24 hours on weekdays.
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Shipping Information
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