Sheet Metal Gas Vent Pipe; Type Double Wall, Round, B; Size 4 Inch Inner Diameter x 4.5 Inch Outer Diameter; Length 24 Inch; End Type Lock Ring; Material Thickness 0.012 Inch (Inner Wall), 0.018 Inch (Outer Wall); Material Aluminum (Inner Wall), Galvanized Steel (Outer Wall); Temperature Rating 400 Deg F; Insulation Supplied Yes; Inclusions/Features Cap; Applicable Standard UL 441; Clearance 1 Inch
3 to 12 inch pipe and fitting couplers overlap 1-3/8 inch when joined together Therefore, assembled length is 1-3/8 inch less than listed length The allowable minimum clearance to combustibles is 1 inch A full set of installation instructions are supplied with caps and supports