The Park Tools Chain Wear Indicator is a Go / No-Go gauge designed to accurately indicate when a chain reaches 0.5% and 0.75% wear - the point at which most chain manufacturers suggest replacement. The chain should be replaced soon if the 0.75% side fits into the chain, before other drive train components also start to wear out fastFeatures:10-speed compatibleMade from precision, laser cut steelLonger design measures a greater length of chain, giving greater accuracy