ShelterPro Chimney Liner is highly recommended to protect the home from flue fires and creosote buildup. Made from 316 stainless steel, it's designed to reline existing chimneys or to be sued in new construction. Made from a continuous strip of 7-ply stainless steel that is interlocked and crimped to proudce a gas- and water-tight lining system of superior strength and durability. Its corrurgated construction allows for expansion and contraction during heat up and cool down periods, removing any stress on the system. Available in 7 lengths, from 20' to 50'.