Pentair Pentek DGD-7525-20 Big Blue Water Filter, 20-Inch Whole House Sediment Filter Cartridge Replacement, Dual-Gradient Density Spun Polypropylene, 20" x 4.5", 25 Micron, Pack of 1, WhiteKEEP YOUR WATER CLEAN and protect your appliances by removing dirt, sand, silt and particulates FITS ALL 20" Big Blue or other heavy duty housings and can replace any 20" x 4. 5" sediment filter cartridge ACHIEVES UP TO 3X the dirt holding capacity of similar size sediment cartridges NSF CERTIFIED for your peace of mind REPLACE EVERY 6 MONTHS or when you notice a drop in water pressure or quality