Lengths Available: 20ft. - 50ft. Diameter Available: 5" / 5.5 "/ 6" / 7" - Our 316 premier heavywall liner only .016 thick the thickest liner on the market - designed to reline existing chimneys or to be used in new construction. Manufactured using in the highest grade mill certified alloys. Manufactured with a continuous strip of stainless steel,interlocked and diagonally crimped to produce a gas and water tight system of superior strength.