The Park Tool Chain Checker (CC-3.2) is a Go / No-Go gauge designed to accurately indicate when a chain reaches 0.5% and 0.75% wear. Replacing a worn chain promptly prevents accelerated wear on sprockets and other drivetrain components. This tool features a longer design for greater accuracy and is compatible with 10-speed chains. It is made from precision, laser-cut steel in the USA and is covered by Park Tool's limited lifetime warranty.