Maximum protection is essential when pushing your engine to the limit. Racing, tow sports and fishing applications require your engine to operate under extreme conditions. Operating at high engine output and high temperatures or alternating between periods of high RPMs and throttling down to low RPMs or idle puts serious pressure on engine oil. Mercury Racing Four Stroke oil will not break down under these conditions. It maintains its viscosity, protects against varnish buildup and sludge formation and exceeds the rust protection requirements for NMMAR certification.