The XLC TO-S82 chain wear indicator is the perfect tool to determine when the chain needs to be replaced. This chain wear indicator is easy to use: insert the curved end into a gap between the chain links and gently let the other end drop into contact with the chain. If the indicator falls through the link without coming into contact with another link, the chain is worn and can be replaced. If the chain checker does not drop through the link, the chain can last a while longer.XLC TO-S82 chain wear indicatorFor 7, 8, 9, 10 and 11 speed road and mountain bike chainsXLC Article number: 2503617801 EAN code: 4055149138189 Retail packaging: Yes