Pentair Pentek Big Clear Filter Housings offer the versatility to meet all of your large-capacity filtration needs, including high-flow and heavy-sediment applications. The extra large housing allows for greater cartridge capacity, reducing the number of vessels required for high flow-rate applications. Sumps are available in both 10" and 20" lengths. The cap is available with 1" NPT inlet and outlet ports. The 1-1/2" internal port allows a greater volume of liquid to pass through the cap more rapidly. Big Clear Filter Housings offer on-site examination of flow, performance, and cartridge life and are ideal for a variety of applications. The 1" polypropylene caps are available with a pressure-relief button on the inlet side to relieve pressure inside the housing . Caps are constructed of reinforced polypropylene. The 10" sumps are made of Lexan and the 20" sumps are SAN (Styrene acrylonitrile).