This 4 Inch x 60 Inch Pellet Chimney Flex Pipe from the PelletVent Pro series is a Type B gas component and consists of the duralock system for a tight seal. Use for offsetting rigid pipe around smoke shelf in masonry chimney only. Allows for offsets with biofuel appliances. Female and male ends twist-lock. Female end swivels for easy alignment. 60 flex section. Not for use in attic or wall spaces.Finish: Stainless Steel Fuel Type: BioFuel, Oil, Pellet Length: 60 Material: Galvanized Steel, Stainless Steel Pipe Class: Type L Pipe Inside Diameter: 4 Pipe Shape: Round Style: Contemporary Modern UL Listed: Yes Vent Construction: Double Wall Weight: 9