3M™ Duct Tape 3939 is composed of a waterproof polyethylene film over cloth scrim backing with a rubber adhesive used for demanding duct tape applications. 3M™ Duct Tape 3939 is the all-around holding, splicing, masking, patching, sealing and seaming tape. A polyethylene coated cloth backing with rubber adhesive offers high tack, conformability, strength and easy tear. The individual roll wrap preserves integrity of the roll for less waste and the product number is printed in core to insure the correct product is used. It features good moisture resistance and has good tensile strength.