20-inch Big Blue filter housing accepts all standard 20-inch Full Flow (BB) filters. The black housing cap features a 3/4-inch NPT pipe size and is made of a heavy duty construction using high-quality FDA grade polypropylene. It has superior chemical resistance from many aggressive chemicals. The housing lid features a buttress thread design for superior sealing and security. The thick side walls are made with heavy duty ribs to provide greater strength. It is rated at temperatures up to 100 degrees F (38 degrees C) and the water pressure is rated up to 90 PSI (6.2 BAR). The cap, sump and top seated O-rings are compressed to provide leak proof sealing.