Park Tool CC4 Chain Wear Indicator

Chain Wear Indicator, The tool works on any 5 to 12-speed derailleur chain (including SRAM AXS) and is designed to accurately indicate when a chain reaches .5% and .75% wear, Takes the guesswork out of determining when a chain is worn out, Accurately measures wear on all 1/2" pitch bicycle chains, Compatible with all 5-to-12 speed chains