Pentek DGD-7525 # 155355 Big Blue 25 Micron Replacement Sediment Water Filter Cartridge Compatible With Culligan / Ametek / US Filter / Plymouth / Kleen Plus / American Plumber / Bruner & Many Other Brands. Big Blue 25 Micron Dual Gradient Polypropylene Sediment Water Filter. 10" long X 4 1/2" diameter. 8 per case, sold individually. Ametek # 155355 DGD Series is manufactured from 100% pure polypropylene fibers and are sized for use in our Big Blue® filter housings. They are designed for purity and will not impart taste, odor or color to the liquid being filtered. Also, the polypropylene construction provides superior chemical resistance and is not prone to bacterial attack. The DGD Series advanced design combines selective "final filtration" with appropriate "pre-filtration." The larger diameter of the pre-filter, prefilter, pre filter reduces the particle load to the post filter, allowing it to operate at higher velocities. This increased depth provides for very high particulate reduction efficiencies and loading capacities. Order a case of 8 and save even more.