Genuine Briggs & Stratton 32 oz. bottle of high quality SAE 5W-30 detergent oil. Using Synthetic oil offers better wear control of your engine, even under severe operating conditions. Since synthetics have better "inherent strength" they have the ability to keep functioning at the highest level for the longest possible time. Synthetic Oil gives your engine better viscosity temperature response, better low temperature fluidity, better thermal stability better oxidation stability, lower volatility, better deposit control, and better wear control. This in return reduces risk of equipment failure, promotes trouble free operation, reduces maintenance costs, extends service life, and long term engine durability.