The DVL 5-6 Double Wall Stovepipe Increaser is a component that is used in a typical venting installation. Use to increase from a smaller appliance flue outlet to larger diameter chimney or stove pipe.Fuel Type: Wood Material: 26 Gauge Aluminized Steel Pipe Class: Stove Pipe Pipe Inside Diameter: 6 Pipe Shape: Round Style: Contemporary Modern UL Listed: Yes Vent Construction: Double Wall Weight: 2