This Genuine Tohatsu Marine Part is a piston (0.5 O/S) with the part number 3B2-00004-1. It is a high-quality replacement part designed specifically for Tohatsu outboard motors. The piston is an essential component of the engine's combustion system, responsible for compressing the fuel-air mixture and transferring power to the crankshaft. This particular piston has been manufactured with a 0.5 oversize, indicating that it is slightly larger than the standard size to accommodate engine wear or cylinder damage. It is crucial to use genuine Tohatsu parts to ensure optimal performance, reliability, and longevity of your marine engine.