This 4 Inch Pellet Chimney Vertical Cap from the PelletVent Pro series is a Type B gas component and consists of the duralock system for a tight seal. Use for vertical installations only. Required where pipe terminates above the roof line.Finish: Stainless Steel Fuel Type: BioFuel, Oil, Pellet Material: Galvalume Pipe Class: Type L Pipe Inside Diameter: 4 Pipe Shape: Round Style: Contemporary Modern UL Listed: Yes Weight: 1