This 3 Pellet Wall Thimble with Air Intake from the PelletVent Pro series is a Type B gas component and consists of the duralock system for a tight seal. Allows outside fresh air for combustion through the wall thimble without having to cut a second hole into the wall.Comes with an insulation ring to reduce air infiltration where the pipe slips through the thimble The 2 diameter, 18 length flex hose expands to 5Â’ Clamps included Can be used in US and Canada PatentedADA Compliant: No Collection: PelletVent Pro Depth: 4 - 8 Finish: Stainless Steel Fuel Type: BioFuel, Oil, Pellet Inside Diameter: 3 Length: 13 Material: Aluminum Pipe Class: Type B Pipe Shape: Round Style: Contemporary Modern Vent Construction: Double Wall Weight: 5 Width: 13