4" DuraVent DirectVent Pro Aluminum High-Wind Sconce Termination Cap 46DVA-HSCH This termination cap is used for horizontal through-the-wall termination and provides improved performance in high wind conditions. Check installation instructions for restrictions on horizontal cap terminations such as minimum distance from windows and doors. Includes heat deflector that may be required by appliance manufacturer. Provides combustion air and exhaust venting for gas appliances Clearance to combustibles mandated by appliance listing The components twist-lock together for a quick secure fastener-free installation 0.020" aluminum inner 0.018" steel outer Offsets venting obstructions .020†aluminum inner wall .018†galvanized steel outer wall Painted outer walls made of laser welded .018†galvalume steel. Caps also available in stainless steel and copper. Outer pipe brings combustion air to the appliance. Inner pipe exhausts flue gases to the outside. Gaskets or sealants not required (unless specified by the appliance manufacturer).