Chimney 69260 Simpson DuraLiner- 6 in. x 24 in. Rigid Liner Use to reline masonry chimney with 0/0 clearance. Built-in, pre-drilled fittings for riveting joints. 304 stainless steel inner and aluminized steel outer walls. Factory insulated with a 0.5" insulation blanket Manufacturer's Limited Lifetime Warranty