The BRIGGS & STRATTON 84003122 Engine Piston Assembly helps convert combustion pressure into mechanical motion for reliable engine operation. Positioned inside the engine cylinder, the piston moves up and down as the air-fuel mixture burns, transferring force through the connecting rod to the crankshaft. This movement helps produce the power needed to operate the equipment. A properly... https://www.wholetoolbox.com/briggs-stratton-84003122-engine-piston-assembly/84003122.html