6" & 8" DuraVent DuraTech Adjustable Extended Roof Bracket 6DT-XRS This adjustable extended roof bracket provides additional support for the chimney when the chimney extends more than 5" beyond the roof; the legs will extend to handle varying roof slopes. New sandwich clamps allow legs to be extended to any length from 67" to 114". No drilling required. Approved for most fuel types 430-alloy stainless steel inner wall 2" clearance to combustibles ThermalTech blanket insulation eliminates hot spots Twist-lock connections for strong secure fits Able to vent large fireplaces and building heating appliances Clean smooth exterior finish 10â€-24†diameter pipes feature an .027†430 stainless steel inner wall and an outer wall of .029†galvalume or .027†430 stainless steel. A Refractory insulation is encased between walls. Only stainless pipes use the stainless end rings. Regular galvalume pipe uses galvalume end rings.