Valve Spring Compressor C Clamp Service Kit Auto Motorcycle ATV Small Engine Valve Spring, Seal and Keeper Replace Tool Fits Valve Retainer sizes of: 16mm (0.630") (OD) -14.5mm (0.571") (ID) 19mm (0.748") (OD) -16.5mm (0.650") (ID), 23mm (0.910") (OD) -21.5mm (0.846") (ID) 25mm (0.980") (OD) -23.5mm (0.930") (ID), 30mm (1.20") (OD) - 28.5mm (1.120") (ID) Each collet length is 50mm (1.975") with window opening of 35mm (1.375")