Pentair 072173 Stainless Steel Flat Washer Replacement Pool/Spa Filter and Pump Flat washer replacement Fits Pentair Star, Star Polymeric, SM & SMBW 4000 and 2000 series filter systems Also fits Pentair EQ-Series commercial plastic pumps Made of stainless steel Measures 3/4-inch length by 1/4-inch height by 3/4-inch width