Pentair 20" Big Blue Housing with Pressure Release Valve

This 20" Big Blue filter housing accommodates most 20" filter cartridges with 4-1/2" diameters. Large housing size makes this unit perfect for high flow-rate applications. 1", or 1.5" NPT inlet and outlet port options are built into the cap. Also built into the cap is a pressure release that relieves pressure before changing filter cartridges. Recommended Filter: STAGE 1 - Sediment Filter 5 mic (155358-43) Replace every 6-12 months or STAGE 1 - Carbon Block Filter 10 mic (155783-43) Replace every 6-12 months