Venting System Chimney Liner Kit; Type Gas Appliance; Applicable Standard UL (Canada and US); Diameter 4"; Length 25'; Kit Content 2-Ply Aluminum Liner, Chimney Flashing, Rain Cap, Mortar Collar, (3) Screw; Used On Item Category I Natural Draft Gas Fired Heating Equipment and Gas Fireplace; Material Aluminum; Warranty 25 Year Limited