Fasson 0800 is used to tape and seal joints and seams on fibrous duct boards in the HVAC segment. Delivered On High Tensile Aluminum Foil Facestock with An Antimicrobial Acrylic Adhesive, These UL 181 AP / B-Fx Registered Tapes Are Used In Hvac Mechanical Installation To Seal Aluminum Duct Work and FSK Board. Come with A 20 Year Limited Warranty.Used To Seal Joints and Seams On Fiberglass Duct Board and Flexible Duct In The Hvac Market. UL 181 A-P /B-Fx Classified.