64 OZ Duct Seal, Fiber Reinforced, Water Based, Premium Quality, High Velocity For Commercial & Residential Supply & Return Air Duct Use, Recommended For Sealing Joints, Seams, & Duct Wall Penetrations On Metal Air Duct, Recommended For Sealing Connections On Flexible Duct Or Fiberglass Duct Board, Crack & Peel Resistant, Mold & Mildew Resistant, Indoor & Outdoor Use, UL Listed 181A-M/B-M, LEED Qualified.