Detailed Description: 4 Housings of 20 Inch big blue filter housing PVC 1 inch NPTF in/out ports pressure release button and 1/4 inch pressure gauge hole and plug. Specifications: Double O Ring 20 inch Big Blue 1 inch inlet and outlet ports Pressure release valve PLUS built in PLUS 1/4 inch PRESSURE GAUGE HOLE + Plug in case you would like to use it without gauge. Accepts 20 inch x 4.5 inch diameter cartridges Maximum Temperature: 125°F Maximum Pressure: 90 psi Blue Housing: polypropylene Black Cap: polypropylene Double Black O-ring