Pentair WC137-517P 21-Inch Collector Hub Assembly for Sta-Rite Cristal-Flo T-BP Series High-Rate Sand Filter Collector hub assembly replacement Fits Pentair Sta-Rite Waterford pool and spa sand filter system models JSAL210D, JSAL210E, JSAL210F, JSALS210F Also fits Pentair Sta-Rite Cristal-Flo high-rate T-BP series sand filter model T-200BP-1 Measures 22-3/4-inch length by 5-1/2-inch height by 5-1/2-inch width