Our poly filter housings are manufactured from the highest quality, FDA grade, 100% polypropylene and acrylic styrene (for clear housings). Leak-proof sealing is accomplished by compression against a top seated EPDM O-ring located in the housing's sump. Thick wall and added ribs make the housings ideal for a wide range of applications. Polypropylene construction provides excellent chemical resistance with most acids, alcohol, ammonia, oils, plating solutions and many aggressive chemicals. Housings supplied with and without pressure relief valves.