Water Filter Housing Ideal for a wide range of applications including residential, commercial and industrial. Pressure-relief/bleed button on inlet side of cap. Thick walls for increased strength. Leak-proof sealing with top-seated Buna-N O-ring Standard filter housings are manufactured of a durable polypropylene. All housings are equipped with 1/2", 3/8" 3/4"and 1", NPT inlet and outlet ports. Reinforced polypropylene housings have excellent chemical resistance and are ideal for many residential, commercial and industrial applications. They offer on-site examination of flow and have excellent chemical compatibility as well.