.D. Water Heater Flex Hose With 3/4 Inch FIP x Features: Durable construction of Corrugated tube 3/4 FIP swivel female threads allows for hassle-free connections To connect gas and electric water heaters and water softeners to the main cold & hot water lines For Indoor use only Eliminates the need of a dielectric union reducing time and installation costs Use a soft pliable Nitrile rubber washer to get a good seal using less torque.