NEOPERL HT Series plastic check valves are pre-assembled and 100% tested to provide durable drip-tight operation. Designed for drinking water and hot water systems, the check valves are available in 12 outer diameter sizes between 3/8" and 2" for drinking water applications (NSF 61) up to 200°F and 230 psi. This new HT Series features Noryl/EPDM construction, which offers superior resistance to chemicals and temperature (up to 250°F).