Designed for appliances tested and listed for direct vent. Features a fully unitized twist-lock construction in both 4 x 6-5 8 and 5 x 8 vent sizes. Use of sealant is optional, unless specified by the appliance manufacturer. To calculate install length, subtract 1-1 2 for each joint. No beads or hems. Black pipe lengths feature exterior laser-welded seams.ADA Compliant: No Fuel Type: Gas, Liquid Propane Height: 9 Material: Black Galvanized Steel Pipe Class: Direct Vent Pipe Inside Diameter: 4 x 6-5 8 Pipe Shape: Round Style: Contemporary Modern UL Listed: Yes Vent Construction: Double Wall Weight: 2