This is a replacement o-ring for pool pumps, an aftermarket part that is compatible with the part numbers for the Original Equipment Manufacturers (OEM) below. These compatibility assertions are made by Aladdin Equipment Manufacturer. Dimensions: 2" x 2-1/2" (approx 2" in diameter) Compatibility / Fits Into Model Numbers: American Products™, AquaPure®, Power Pak® III, Sta-Rite®, SwimQuip™, WC212-1438, 144P, 138B, S7M120, S8M150, PlusHP PHPF & PHPM, MaxHP MHPM/WFTR OEM Part Numbers that this part is compatible with: 308-1227, R0452100, R0449200, R0412700, 80231, 39006600, U9-362, 35505-1245, N-231/N231, O-2111 Other Compatibility Includes: Doughboy® 308-1227, Jandy® R0452100, R0449200, R0412700, Lasco 80231, Praher N-231/N231, SSC O-2111, Tesco Also known as: O244