Swimming Pool Check Valve, 2in Visible Check Valve Non Return Anti-Backflow Accessories for Swimming Pool One-Way Pipe The installation is simple and does not require complicated operations, save time and effort. Wide range of uses, suitable for swimming pools, hot spring sauna pools, baths. Installed at the outlet of the water pump to prevent water backflow and damaging the pump impeller. Specification: Item Type: Check Valve Material: ABS+PVC Weight: Approx. 727g/25.6oz Nominal Diameter of Interface: Approx. 2in/60.2mm Purpose: Install at the outlet of the water pump to prevent water from flowing back and damaging the pump impeller Package List: 1 x 2in Check Valve Features: High-quality material, transparent and visible, anti-and, simple installation Installation and use instructions: 1. Determine whether the diameter of the pipe to be installed is consistent with the installation diameter of the valve. The nominal diameter of the valve is: 2 inches 2. Before the valve is used, a manual operation test should be performed to observe whether the sealing baffle of the valve will rebound to the original position to determine whether the valve is damaged during transportation 3. Before installing the valve, check: A. Whether the water pump on the pipeline used is in the closed state: B. Whether there is debris in the valve cavity, and keep the inner cavity of the door : C. The flow direction marked on the valve must be consistent with the flow direction of the pipeline liquid. 4. Before installation, the oil stains or other debris on the installation nozzle and inside the valve installation port. Note: 1. When connecting the valve nozzle with the pipe nozzle, please use special PVC glue. 2. Please allow 02cm error due to manual measurement. Thanks for your understanding.3. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.