Gates HK9RB Blue Racing Hose Kit Durable nylon fiber provides extra wear resistance, doubling tooth strength Kit contains 1-Upper radiator hose (22721 - 10.864 inch centerline length, 1.32 inch inner diameter) and 1-Lower radiator hose (22720 - 16.278 inch centerline length, 1.32 inch inner diameter). Protects against the high temperatures of full throttle driving Combats the leading cause of premature hose failure - electrochemical degradation (ECD) High saturation HNBR elastomeric composites contribute to the exceptional durability and heat resistance with aramid reinforcement