CHAIN CHECKER PARK CC-3.2The CC 3. 2 is a go no go gauge designed to accurately indicate when a chain reaches . 5% and . 75% `stretch,` the points at which most chain manufacturers suggest replacement For 9 and 10 speed chains, replace chain just as the gauge fits the 0. 75% side fits flat into the chain for 11 and 12 speed chain, replace as the 0. 5% side fits Long, accurate and features permanent measurement markings Works on most derailleur chains from 5 to 12 speed