Max Motosports Cylinder Piston Rebuild Kit Assembly Fits Husqvarna 55 51 Chainsaws 46mm # 503 16 91-71 REPLACES OEM 503 16 91-71 Bore 46mm Fits:HUSQVARNA 55 Chainsaw This is a new aftermarket Cylinder and Piston Kit for Husqvarna 55 51 Chainsaw directly Notice:Will also work as an oversize kit for a 51 chainsaw