Pentair Skimmer Flap Weir fits Pentair Admiral Skimmers. Choose flap weir for optimal water flow and superior surface skimming action. Skimmer weir is a door used to close the skimmer when it is turned off to prevent debris and dirt from entering the skimmer. It adjusts on the pool water level on its own. It traps leaves that are pulled into the skimmer when the pump is running and then holds the leaves in the skimmer when the pump shuts down. Pool Vac stocks a complete line of Flap Weir Assembly for your Pentair Admiral Skimmer replacement parts.