COMPLETE SET: Includes everything you need for the filter housing installation, including three 20” BB housings, double o-rings, a filter wrench, and metal mounting bracket. UNIVERSAL SIZE: Standard size 20” x 4.5” BB 3 water filter housing is compatible with any 20x4.5 filter cartridges, including sediment, carbon, water softening, and more. HIGH FLOW: Provides a standard-size 1” NPT thread inlet/outlet connection for optimal water flow. HEAVY DUTY: Composed of premium polypropylene with reinforced construction for durable 20 inch housings. SAFE & CLEAN: Our #20 BB three-housing is made from food grade material to safely improve your water quality. SpiroPure 20" x 4.5" Triple BB Water Filter Housing with Pressure Relief Button, 1" NPT. This item includes 3 blue filter housings, a wrench, and mounting bracket.