Bel-Ray EXS Full Synthetic Ester 4T Engine Oil Synthetic ester with extreme pressure (anti-wear) additives delivers ultimate protection and horsepower. Longest change intervals for air-cooled/liquid-cooled 4T engines with wet clutches. Superior transmission and wet clutch performance. Features: EXS full synthetic ester 4T engine oil uses the finest quality synthetic hydrocarbon and ester base fluids combined with unique extreme pressure, anti-wear additives and shear resistant VI improvers to meet the demands of high-performance applications Lowers engine temperatures and increases horsepower Meets the performance requirements of API SM and Jaso MA2 Suitable for air-cooled/liquid-cooled 4-stroke engines and wet clutches