20-inch blue filter housing accepts Slimline filters. The black housing cap features a 3/8-inch NPT pipe size and is made of a heavy duty 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 125 degrees F (52 degrees C) and the water pressure is rated up to 125 PSI (8.75 BAR). The cap, sump and top seated O-rings are compressed to provide leak proof sealing.