S-4sr snowmobile 4-cycle oil with nascar® proven technology is a 100% synthetic formula designed for high stressed 4-cycle racing engines in the most severe conditions.S-4sr is an mpz® fortified formula that offers the ultimate in viscosity control, anti-friction, anti-wear and improved power output.It is formulated to reduce engine temperature and wear from high load conditions.A selective additive system and polymer chemistry also provides anti-oxidation, anti-foam, and anti-rust features to keep engines protected.S-4sr offers the best protection for engines running at high rpm, high temperatures and under extreme loads or endurance type conditions.S-4sr is recommended for use in air cooled or liquid cooled snowmobile 4-cycle engines commonly found in arctic cat®, polaris®, ski-doo®, yamaha® and other snowmobile applications.