Pentair Pentek Valve-in-Head Filter Housings incorporate the same rugged design and application features as our Standard 3/4" NPT Housings. The internal valve-in-head allows both inlet and outlet ports to be simultaneously shut off with a half turn of the handle. This eliminates the need for external shut-off valves. Radial sealing O-rings and sealing surfaces are continuously cleaned each time the valve is used, ensuring leak-proof operation. Valve-in-Head Filter Housings are available in both 10" and 20" lengths, and will accommodate a wide range of 2-3/8" to 2-7/8" diameter cartridges. The polypropylene caps feature a pressure-relief button on the inlet side to relieve pressure inside the housing when changing filter cartridges. Opaque Valve-In-Head Filter Housings are molded from rugged reinforced polypropylene, offer outstanding chemical compatibility, and are ideal for use in a variety of low-flow applications. These applications include under-sink and countertop residential filtration, pre- and post-reverse osmosis filtration, recreational vehicle filtration, foodservice, and humidifying systems. Clear Valve-In-Head Filter Housings offer on-site examination of flow, performance, and cartridge life. They are also ideal for a variety of applications.