BLUE Pentair Pentek Traditional Standard Filter Housings are manufactured of a durable polypropylene or clear Styrene-Acrylonitrile (SAN). All are equipped with 3/4" NPT inlet and outlet ports. Standard Filter Housings are available in both 10" and 20" lengths. The reinforced polypropylene cap offers an optional pressure-relief button on the inlet side to relieve pressure inside the housing when changing filter cartridges. Opaque Standard Filter Housings are molded from rugged reinforced polypropylene. They offer outstanding chemical compatibility and are ideal for use in a variety of low-flow applications. Clear Standard Filter Housings offer on-site examination of flow, performance, and cartridge life. They are ideal for a variety of applications.