3M™ Glass Cloth Electrical Tape. 3M™ Glass Cloth Electrical Tape 27 is a 7 mil woven insulating tape with pressure sensitive rubber thermosetting adhesive. This tape is designed to operate in 600 volt dry applications requiring high mechanical strength and resistance to high temperatures. The adhesive is specially designed and prepared to provide corrosion protection. 3M™ Glass Cloth Tape 27 is edge tear resistant, conformable, and abrasion resistant. For use as a coil cover, anchor, banding and core, layer and crossover insulation. UL Recognized. Printable.