PEDRO'S CHAIN CHECKER PLUS IICHIGGITY-CHECK YOURSELF BEFORE YOU WRECK YOURSELFUnfortunately, all moving parts on a bike will wear out eventually. Some, like the chain, will wear out quicker than others. When your chain starts to wear out, it will consequently start wearing out other parts like the cassette and chainrings with it. In order to keep your chain from prematurely wearing out your cassette and chainrings, you need to check it to see how worn out it is. The Pedro's Chain Checker Plus II has a precision laser cut design that accurately measures 0. 5% and 0. 75% chain wear. The three-point chain wear tool design properly isolates pin wear from roller wear. Don't let your chain get too worn out, check it with the Pedro's Chain Checker Plus II. Features 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 | Pedro's | Chain Checker Plus Ii Black