Gates 18565 Molded Heater Hose , 14.5" Centerline Length, 0.63" and 0.75" ID, Black Inside Diameter 1: 0.63" Hose Inside Diameter 2: 0.75" Approved for marine applications Meets SAE 20R3 Type EC Class D-1 and D-2 specifications Temperature Range: -40F to +275F in coolant hose applications