6" DuraVent DuraPlus Adjustable Extended Roof Bracket 6DP-XRB 6" DuraPlus Adjustable Extended Roof Bracket is used to support the chimney when it extends more than 4' above the roof. Provides stability to chimney against wind and snow. Mounting brackets and adjustable legs included. Diameter: 6" Adjusts 67" - 114" Mounting brackets and adjustable legs included .016†430 stainless steel outer wall or .018†galvanized steel outer wall. .018†aluminized steel intermediate liner. .016†430 stainless steel inner liner. Insulated layers plus ventilated air space. Locks tightly with a precision twist-lock connection.