【PVC Ball Check Valve】Schedule 80 PVC ball check valves have a spherical ball inside the valve body which works as a check to allow flow in one direction and close off to prevent back-flow. 【PVC Spring Check Valve】PVC union check valves have a stainless steel spring inside, are designed for both vertical (upflow position) and horizontal installations, PVC spring check valves MUST be installed with the valve's flow arrow pointing in the direction of the flow. Do not install valve upside down. 【PVC Union Check Valve】PVC spring pool check valve, can be taken apart for cleaning, allows for easy removal without breaking down the piping connection. 【Material】 3/4inch Slip one way check valve made of PVC material, O-ring with EPDM material, stainless steel spring, low-temperature-resistant, impact-resistance, ultraviolet-resistance, rust-resistance. Fits for Schedule 80 3/4inch Pipe. 【Application】PVC Swing aquarium Check Valve 3/4’’ (DN20) - Non-return or "one way" valve is ideal for flow control, such as commercial plumbing, aquariums, irrigation, swimming pools, water parks and OEM applications. PVC Spring Ture Union Check Valve, 3/4in Slip Swing Utility Water One Way Check Valve, Sch80 Socket Pool Ball Check Valve for Backflow Prevention Specification: For use with: water Type: check valve Connection type: Pipe Connection: Socket Schedule: 80 O-Ring Material: EPDM Cracking pressure: less than 5psi Mounting: horizontal or vertical up-flow Max pressure: 150psi Maximum service temperature: 140℉（60℃） Features: Engineered for maximum flow, quick response & positive shutoff Excellent for pool &spa, OEM and general purpose applications Compact, space-saving design Stainless steel spring, vertical and horizontal installation Package: 1Pc PVC union spring check valve