The DirectVent Pro 4" x 6-5/8" Inner Diameter Galvanized 36" Pipe Length (Black) is a component that is used in a typical venting installation. The DuraVent 36" direct vent pipe is designed for appliances tested and listed for direct vent. Features a fully unitized twist-lock construction in both 4"x6-5/8" and 5"x8" 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. Features: Finish: Black. Fuel Type: Gas. No Beads or Hems. Pipe Shape: Round. Pipe Class: Direct Vent. Collection: DirectVent Pro. Material: Galvanized Steel. Inner Pipe Material: Aluminum. Outer Pipe Material: Galvanized Steel. Fully Unitized Twist-Lock Construction. Designed for Appliances Tested and Listed for Direct Vent. UL Listed. Specifications: Overall Dimensions: 36" (L) x 6.62" (W). Inner Pipe Gauge: 24. Outer Pipe Gauge: 28. Pipe Inside Diameter: 4".