Compatibility: Fits multiple engine models including 540477, 541477, 541777, etc., and some 540000, 541000, 542000 Briggs & Stratton engines. Replacement Part Numbers: 809732, 540477, 541777, 613177. Function: Seals the connection between the valve cover and cylinder head, preventing oil leakage and ensuring interior air-tightness. Material: Made of rubber/fiber composite with excellent sealing, high-temperature, high-pressure resistance, and good wear-resistance and durability. Benefits: Ensures a secure fit and proper sealing, enhancing engine performance and longevity.