Thermoplastic - Size SB25 (Nominal Hose I.D. 5/8", Fits Hose O.D. 15/16" to 1 1/16"). Gates thermoplastic clamp maintains a dynamic tension so that it never needs retightening. Made of a heat-sensitive material, Gates PowerGrip™ SB clamp solves coolant leakage problems in both silicone and standard rubber wall hoses, even on out-of-round fittings.