System 636® concentric kits, are available in a variety of lengths and come in 2 in, 3 in and 4 in diameters. These pipe-in-pipe kits allow for both exhaust and intake pipes to penetrate the roof or side wall through only one hole. The concentric vent kits are now certified with mechanically fastened rain caps. When installed with the included stainless steel screw or nut the rain cap can be easily removed for cleaning or replacement. Vent screens and round face plates for side wall terminations are also available, see reverse.