Mountain Bike Chain Breaker ToolDesigned to work with most bicycle chains for pressing out the links to lengthen or shorten your bicycle to fit multiple cassette configurationsShop-quality chain tool for most chains single to 11 speedHelps in retracting pin guide supports and guides chain pin out of link and prevents damage and misalignment to the chainGuide pin sheer slot for a clean breakThis tool is for Shimano type HG/UG/IG chains and fits 8/9/11/12 speed cassettes