This Skunk2 radiator cap will slightly increase your internal radiator pressure, which has the effect of raising the coolant boiling point and increasing cooling efficiency. The open valve pressure is 1.3kg/cm2 (or 18.5 PSI) compared to the normal 0.9 to 1.1kg/cm2 for most vehicles. The Skunk2 radiator cap demonstrates its effectiveness under high-load situations such as high-performance and circuit driving. Each Skunk2 radiator cap is made using durable construction from the highest quality materials.