The Topeak Ninja C Tool Storage stores inside your handlebar to keep your pockets free, but can be easily accessed when you need it. This 11 speed compatible chain tool includes a chain pin compartment, chain hook, and 4mm Allen wrench for easy operation. Topeak Ninja C Tool Storage Features Compatible with all chains including Campagnolo® 11 speed hollow pin chains Tough hardened steel construction 4mm allen wrench Fits in to bars with 16.5-20mm internal diameter Chain hook included Integrated chain pin breaker Includes rivet anvil for 11sp Campagnolo hollow pins