Pentair WC137-516P Collector Hub Assembly Replacement Sta-Rite Pool and Spa Sand 18-Inch Sand Filter Collector hub assembly replacement Fits Pentair Sta-Rite Waterford pool and spa sand filter system models JSAL180D, JSAL180E, JSALS180E and JSAL180F Also fits Pentair Sta-Rite Cristal-Flo high-rate T-BP series pool and spa sand filter model T-170BP-1 Measures 21-inch length by 5-3/4-inch height by 5-3/4-inch width