Chain Wear Check Tool, Chain Hook Tool, and Chainring Nut Wrench Precision laser cut design accurately measures 0.5% and 0.75% chain wear Three point chain wear tool design properly isolates pin wear from roller wear Chain hook tool and chainring nut wrench add functional versatility and value Chain wear tool approved by SRAMĀ« for use on EAGLEĀ« 12-speed chains Works on 1-12 speed chains. CHAIN CHECKER PLUS II