It also promotes permanent anchoring in application. Typical applications for 1339 include lead anchoring, banding of coils, lead tape anchoring and other uses where tensile strength is needed. 3M electrical tape 1339 is a polyester film/glass filament tape coated with a pressure sensitive acrylic adhesive system. The polyester film/glass backing has excellent physical and electrical characteristics. The back side of the tape has a special coating which allows for an even, controlled unwind.