A Japanese EDC Brand’s Game-Changing, Affordable New Multi-Tool Revives a 129-Year-Old Design

The new take on a familiar favorite promises enhanced performance in a compact, wallet-friendly form factor.

Close-up of a metallic turntable cartridge with a stylus needle touching a wooden surface.

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By Hayley Helms

Published May 19, 2026

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Some designs are so familiar, we stop questioning them. If it ain’t broke, don’t fix it, right?

Japanese EDC brand Kougu Box doesn’t follow that conventional line of thinking, and good thing, too. Its latest Kickstarter release, the Renchi, reimagines one of the most time-tested tools in any tool kit, the monkey wrench, and improves it it in the process.

Close-up of a metal mechanical component with stacked plates and a small pin on a wooden surface. — The Renchi can also function as a hammer, nail puller, reversible vise, gear hook, torque multiplier and more.

Wrench on it

The Renchi is a modern adjustable wrench built with a self-locking mechanism that can be operated with one hand.

Based on a patent filed by one Terry Coleman in 1897, where the jaw travels along the linear axis of the tool, Kougu Box’s design integrates 12 heavy-duty locking plates into a compact space, adding a robust clamping force to the wrench.

Close-up of a hand adjusting a metal caliper measuring the thickness of green tape on a cardboard box edge. — Renchi also provides a scale for quickly measuring the size of nuts and other items in both inches and metrics. (It also functions as a box cutter.)

The opening stretches all the way to 80mm, which is massive in comparison to an average monkey wrench, which hovers around 20 to 40mm. The serrated jaw adds extra grip for tougher jobs.

Close-up of a stainless steel caliper with numbered labels on various parts against a white background. — The Renchi consists of five parts: 1. Locking Plate, 2. Spring, 3. Adjustable Jaw, 4. Switch, and 5. Handle.

The adjustable wrench doesn’t just open wider and adjust easier than traditional designs; thanks to its self-locking mechanism, the Renchi eliminates the jiggling found in conventional tools, which can lead to slipping and subsequent rounding of bolt heads.

Close-up of a metallic object with a textured, grooved surface and a smooth, angled edge. — The serrated jaw tip allows for maximum bite force and grip.

Constructed with just five parts, the Renchi is easy to disassemble, clean and put back together. At just 10mm thick, the ultra-slim profile is ideal for tough-to-reach jobs.

Close-up of a metal caliper showing both metric and imperial measurement scales. — With laser-etched scales in both systems, Renchi doubles as a reliable caliper.

The Renchi is built with four types of high performance steel:
chrome vanadium (Cr-V) steel, Japanese SK-5 steel, chromium-molybdenum steel (Cr-Mo) and SUS304.

This material blend pairs maximum strength with unmatched durability, making this a tool that will stand the test of time.

Availability and pricing

The Renchi Super Early Bird deal is available now on Kickstarter for $88. Only 13 units at that rate remain at the time of writing, so act fast to get the best deal. Estimated delivery is (sigh) March 2027.

Close-up of a metal caliper measuring the thickness of cardboard with green tape on the edge.

Kougu Box Renchi

$88 at Kickstarter

About the Author: Hayley Helms is an associate editor at Gear Patrol specializing in outdoor gear. Once upon a time, she wrote for Men’s Journal, Gearjunkie and Shape. Whether it’s testing a new rain shell or putting a pair of hiking boots through its paces, she leaves no stone unturned (however, she always Leaves No Trace).

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