RS 4-cycle engine oil is a full synthetic, triple ester based race-grade oil. Technologically advanced formula contains special anti-wear/extreme pressure additives to protect critical engine components from extreme loads and peak temperatures generated by high-performance engines. RS delivers increased horsepower and torque, superior engine cleanliness, reduces wear on bearings, cams, lifters, crankshafts and extends engine life. The high zinc/phosphorous formula is engineered for use in flat tappet and roller element engines. Compatible with petroleum and synthetic engine oils. The oil does not require the addition of additives or boosters. Not recommended for street use.