Summit GEO PS-130 and GEO PS-140 are low ash, balanced medium TBN gas engine oils manufactured from a blend of synthetic and mineral base stocks to optimize performance at a lower operating cost versus the full synthetic formulations like Summit GEO SH (Low Ash) Series or GEO SH-140 CA. Summit GEO PS-130 and GEO PS-140 are recommended for lean or rich-burn service in two-stroke and four-stroke gas engines, naturally aspirated or turbo-charged. They are formulated with the latest in gas engine oil additive technology comprised of superior anti-wear and anti-scuff agents, oxidation & nitration inhibitors and detergent-dispersants to neutralize corrosive gas components, provide excellent protection against valve component recession or beat-in, and disperse combustion by-products for improved gas engine cleanliness and low combustion chamber deposits.