CWF Noritz Concentric Straight Vent Pipe with Wall Flange The CWF is a finely finished stainless steel inner-wall connection vent line piece for your through wall applications. This piece includes a wall flange, has a simple push on connection, anti-corrosive and heat resistant connections, and is compatible with all heaters from the DVC series. As part of the N-Vent series, this product is UL approved category III venting, and is an integral part of the quick-snap connection system, known for easy installation and forming tight seals. The CWF is an inner wall pipe with a built in wall flange to make the installation process easier, and help create a professional look. In addition, the kit is part of the N-Vent series so it's approved for tankless and boiler stainless steel exhaust installations, enabling you to know you've made the right choice in both form and function.Stainless SteelDouble WallL1-2.0"L-8.7"D-8.7"