The Pentair 85000600 is a 9" White Ring Seat Only compatible with Admiral™ S20 Wedge Skimmers. Admiral S20 Skimmers have a PVC reinforced twin port base. S20 may be purchased with equalizer for commercial and NSF applications or for when the second port is connected to the main drain. All models include the innovative lock down lid and are available with a flap weir or the circular weir for greater skimming action.