A-B1697367-AI RING SET-STDOne New Aftermarket Replacement Standard Piston Ring Set Fits Briggs & Fits Stratton Engines This standard (STD) bore piston ring set is an aftermarket replacement Fits Briggs & Fits Stratton small engines commonly found in lawn mowers, lawn tractors, riding mowers, zero turn mowers, generators, pressure washers, and other outdoor power equipment. The ring set seats in the piston ring grooves and forms the critical seal between the piston and cylinder