"Use for a two-piece installation from stove to ceiling support box or finishing collar. Extends 40in. to 68in. No cutting required Double-wall interior stovepipe for connecting wood stoves to manufactured chimney Materials and construction, 0.016 "" stainless steel inner wall, 0.018 "" galvanized outer, painted black DVL's double-wall, air-insulated design reduces clearances to combustibles from 18"" to 6"", the closest clearance to a wall of any connector pipe. DVL improves stove performance by maintaining high flue gas temperatures for a strong, steady draft. Because the inner wall is stainless steel, the flue heats up faster, stays hot longer, minimizes the formation of creosote, and has the same life expectancy as the chimney. Model Number: 8DVL-68TA. Age Group: adult."