The adhesive coating shall be smooth and uniform and be free of lumps and bare spots. There shall be no separator between adjacent layers of the roll. 3M electrical tape 28 shall perform at a temperature of -40 to 221 °F without loss of physical or electrical properties. 3M 28 is an acetate cloth electrical tape with a rubber thermosetting adhesive. This tape shall be coated on one side with pressure sensitive adhesive, which shall not require heat, moisture or other preparation prior to or subsequent to application.