The Crank Brothers TT17 Twin Tube Kit houses 17 tools inside an anodized aluminum case that mounts to standard 64mm bottle cage bosses. The case holds a 16 or 20 gram CO2 cartridge in one tube and provides additional storage in a second tube for a spare chain link or other small items. The included multi-tool covers most trailside repairs with six hex wrenches, a T25 Torx bit, flat screwdriver, three spoke wrenches, valve core remover, and a chain breaker that works with 8 through 12-speed chains. The tool can also install connecting pins for 10, 11, or 12-speed chains. A magnetized section on the multi-tool body holds a quick link for storage.

The integrated CO2 inflator threads onto the body of the multi-tool and works with any threaded CO2 cartridge. You thread the cartridge all the way into the inflator, push the inflator onto your valve, then back the cartridge out a quarter turn to release the gas. The full-size tire lever has enough stiffness to handle tubeless beads, and the back side stores a tubeless plug tool with two spare plugs. The fork-style plug tool grabs the stem of the plug and pushes it through from the inside of the tire, which is the same method used by most tubeless repair systems. Crank Brothers sells plug refill kits separately when you use up your spares.

The spoke wrenches cover size 0, 1, and 2 nipples, which handles most modern mountain bike wheels. The chain tool has dual positions that let you either break the chain or install connecting pins, and the magnetized storage spot keeps a quick link handy without needing to dig through your pack. The entire kit weighs 247 grams and sits low enough on the frame that it stays out of the way when you're riding. The aluminum case threads together at the center and both ends unscrew to access the storage compartments. Crank Brothers includes a five-year warranty with the kit.