3M(TM) PTFE Extruded Film Tape 5491Gray, thicker version of Tape 5490, PTFE extruded film with silicone adhesive 3M(TM) PTFE Extruded Film Tape 5491, Thicker version of Tape 5490, PTFE extruded film with silicone adhesive, provides an exceptionally slick surface when applied and resists curling during unwind. Chemical resistant surface for sealing and masking.