Pentair Admiral™ 84420405 S20 PVC Base Skimmer with Flap Weir and No Equalizer for Concrete Construction White 1.5" Slip Port - The 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 exclusive lock down lid that can be personalized with custom logo disks and are available with a flap weir or the exclusive circular weir for superior skimming action.