PARK TOOL CC-3. 2 CHAIN WEAR INDICATOR A worn chain shifts poorly and wears sprockets at an accelerated rate. The CC-3. 2 is a "go-no go" gauge designed to accurately indicate when a chain reaches . 5% and . 75%, the points at which most chain manufacturers suggest replacement. The updated CC-3. 2 is longer, more accurate and features permanent measurement markings. The CC-3. 2 works on all 1/2" pitch chains, from 1 to 12 speed. Features Related Articles: WHEN TO REPLACE A WORN CHAIN Manufacturer's Part No: CC-3. 2 UPC: 763477001344 | Park Tool | Cc-3. 2 Chain Wear Indicator Cc-3. 2C