***DISCONTINUED PER MANUFACTURER***3M™ PTFE Film Tape 5491, Brown, 4 in x 36 yd, 6.7 mil, 3 Roll/Case. 3M™ PTFE Film Tape 5491 uses an extruded polytetrafluoroethylene (PTFE) film backing. This tape offers an extremely low coefficient of friction which, in combination with a pressure sensitive silicone adhesive, creates a smooth, non-stick surface over a variety of substrates to assist in the movement of materials in many types of lay-flat applications.