The DirectVent Pro 4 x 6-5 8 Inner Diameter Galvanized Restrictor Disk is a component that is used in a typical venting installation. Use only in accordance with specific appliance manufacturer's installation instructions to restrict incoming combustion air.ADA Compliant: No Depth: 6-3 4 Finish: Galvanized Fuel Type: Gas, Liquid Propane Height: 11 - 20 Material: Aluminum, Galvanized Steel Pipe Class: Direct Vent Pipe Inside Diameter: 4 x 6-5 8 Pipe Shape: Round Style: Contemporary Modern UL Listed: Yes Weight: 1 Width: 6-3 4