This Entegris Millipore YY500500 Wafergard T-Line 316 Stainless Steel Housing includes a 6-Stack WGG806S02 Gas Filter. It has a 1/4 Inch (F)NPT pipe fitting. New from the manufacturer replacement cost is over $450. These are in like new condition. They look like they were installed in a clean room environment for a short time and then removed from service.
Head - Bowl Electropolished 316 Stainless Steel - Vitron O-Ring WGG806S02 6-Stack Filter 20 SCFM Flow Rate - 93.6 Cubic Inch Filter Area Port size: 1/4 FNPT 3.75 Inch Diameter 3.125 Inch Height Max Inlet: 150 PSIG - 68F 50 PSIG - 212F