From the manufacturer

A trailside chain failure is the worst kind. You're hours from a workshop, the rest of the ride is back to the car, and you need a chain tool that's actually in a jersey pocket. The Mini Chain Tool+ 1647/5MINI is what fits there. 53 grams, smaller than a tire lever in the long dimension, and it drives a chain pin the same way the workshop tools do.

What surprises most riders the first time they use it is that the small body actually works. The spindle threads are precise enough to push a pin straight, the chain support holds a chain plate against the driving pin, and the handle gives you enough leverage to crack a stiff rivet without slipping. It's not a workshop tool sized down; it's a small tool designed to do one job under conditions where any tool that doesn't is dead weight.

Features

• Compatibility
  The Mini Chain Tool+ covers 5- through 11-speed derailleur chains. That's most of the chains a rider is likely to be on for a long ride: 11-speed road and MTB drivetrains, gravel groupsets in the 11-speed era, anything older with narrower or wider cog spacing back to 5-speed. For SRAM AXS flat-top chains or Campagnolo peening, you want the workshop tool back at the car; the Mini's geometry doesn't carry those inserts.
• The valve-core remover detail
  Open the handle and the inside surface doubles as a valve-core remover. It fits both Schrader and Presta cores; the same slot drives both. This is the second-tool problem that gets solved by carrying one tool: sealant top-up on a tubeless setup, valve-stem swap on a flat repair, presta-to-Schrader replacement on a loaner wheel. The valve-core function is right there, in the part of the handle that already has to be in your pocket.

Specifications

• 5-11 speed derailleur chains
• 67 x 11 x 43 mm
• 53g
• Pin diameter: 6.8mm
• Valve-core remover for Schrader and Presta valves built into the handle
• Article number: 1647/5MINI