ISR Performance Silicone Radiator Hose - Nissan RB25DET - Black ISR Has now released a line of Silicone-based coolant hoses that are designed to take a higher range of heat and coolant pressures than OEM style hoses. Silicone has a much higher strength than the OEM rubber hoses which will prevent the hoses from expanding. ** All ISR Performance Products are Designed for Off Road Use Only ** LEGAL IN CALIFORNIA ONLY FOR RACING VEHICLES WHICH MAY NEVER BE USED, OR REGISTERED OR LICENSED FOR USE, UPON A HIGHWAY