http://www.topeak.com/products/Tools/ALiEN_II Often copied but never duplicated, the award-winning ALiEN II is still the best. A clever break-apart design makes it easy to find and use the right tool. And with 26 high quality tools at your fingertips, you'll rarely find yourself without exactly what you need. There's even a bottle opener for post-ride celebrations! The chain tool is compatible with all single speed and most multi-speed chains, including 10 speed hollow pin chains.