PhonicTrap Acoustic DuctingPHONIC TRAP ACOUSTIC DUCTING Phonic Trap ducting is setting the new standard for silent running extraction systems. It's unique multi layered design dramatically reduces the noise level from any extraction fan. The three tiered laminations is built around a steel helix core with a perforated inner lining, a non allergenic insulation (glass wool free) membrane, and a black vapour barrier. If you use this with any acoustic extraction fan set up you can