Magic Plastics - Inline Check Valve, 2.0in Slip Socket, PVC, 0821-20

Magic Plastics Inline pool and spa plumbing water check valve, 2.0"" slip socket with a 1/2 lb internal spring, Magic # 0821-20. Used to prevent cycling or backflow of water within a 2"" PVC pipe. Installs in one direction only, to keep water moving in one direction only. Often used in front of the pump or heater, or before a chlorinator, to prevent back draining when the system is off.