These install near your skimmer or filter, so if the pump is turned off, it will not back-siphon and dry up.

• Also used to help with priming an external pump. Used on the intake to keep water in the pipe.
  
  
• These PVC swing check valves are recommended whenever maximum flow is needed 
• Swing checks have full flow design for maximum gpm and are completely non-metallic ensuring years of use in water
  
  
• Ideal for use in fresh or salt water, are rated to 100 PSI, mount vertical or horizontal, and can be used with schedule 40 or 80 PVC pipe
  
  
• SLIP x SLIP only