Checking your chain for wear is one of the simplest things any cyclist can do to maintain drivetrain performance and minimize maintenance costs. The Pedro's Chain Checker Plus II makes this task quick and easy offering a simple check of 0.5% and 0.75% chain wear. To ensure the maximum life from your chain and accuracy of measurement, the tool employs a three-point design which properly isolates pin wear from roller wear. The Chain Checker Plus II also includes a chain hook tool, perfect for simplifying chain removal and installation, and a chainring nut wrench, essential for removal and installation of chainrings. Works on 1-12 speed chains. Chain wear tool approved by SRAM for use on EAGLE 12-speed chains.