The Pentair Pentek 150470 Big Blue Filter Housing is a heavy-duty, whole-house vessel built for large-capacity filtration, including high-flow and heavy-sediment applications. Its extra-large 10-inch sump holds 4-1/2 inch diameter cartridges, so you can choose a cartridge that reduces dirt, sand, rust, silt and other sediment for cleaner water throughout your home. The larger housing increases cartridge capacity and reduces the number of vessels needed for high flow-rate systems. The High-Flow Polypropylene (HFPP) cap is fitted with 3/4-inch NPT inlet and outlet ports for rapid flow, and the housing is compatible with a broad range of chemicals. It is Tested and Certified by NSF International to NSF/ANSI Standard 42 for material and structural integrity. The button assembly uses 300-Series stainless steel, EPDM and polypropylene, and the O-ring is EPDM. This 10-inch model is rated to 100 psi maximum and 40 to 100 degrees F, and it ships without a pressure relief button. This is the 10-inch housing, measuring 12.75 by 7.38 inches and accepting 4-1/2 inch diameter Big Blue cartridges. The cartridge, SW-3 filter wrench and mounting bracket are sold separately and are not included. For a leak-free seal, lubricate the O-ring, hand tighten the sump, then add a quarter to half turn, and protect the housing from freezing to avoid cracking.