Large O-Ring 5.48 inch 14 cm actual diameter Replacement for use with: Whole House Sediment Filter AO-WH-PRE. Also fits most filter sumps designed for 4.5" filter elements. Use only genuine A. O. Smith replacement filters for continued contaminant removal and system performance. Keep the water-tight seal on your whole house sediment filter. Use when you change out your filter every 3-6 months. Includes 1 large O-ring, individually packaged.