FLEXMASTER Triple Lock Aluminum Acoustic Perforated Flex Pipe is an insulated acoustic air duct designed to reduce sound transmission. It features a Triple Lock (T/L) perforated core with a 20% to 25% open area, effectively cushioning sound. The inner duct is wrapped in thick fiberglass insulation and covered with a flame-retardant, non-toxic polyethylene vapor barrier. This high-performance duct comes with a vinyl sleeve and is ideal for applications requiring superior noise reduction and thermal insulation.