Expansion Chamber Seal kit for YAMAHA YZ 250 2-Stroke YZ250 and YZ250X Dirtbikes Motorcycles. Kit replaces old factory parts with fresh springs, o-ring seals, and exhaust pipe to silencer coupler. Kit configured to re-seal stock or aftermarket pipe with proper new swivel hook pipe springs, "O" Rings, and Hi-temp silencer to pipe coupler. 3JE-14615-00-00 Replaces factory equipment with exact fit quality parts. Kit comes complete with what you see. Designed to fit YZ250/YZ250X all 2001 to current models. Complete set, nothing else needed to seal up your two stroke exhaust pipe.