Thread seal tape (also known as PTFE tape or plumber's tape) is a Polytetrafluoroethylene(PTFE) film for use in sealing pipes threads. The tape is sold cut to specific widths and wound on a spool, making it easy to wind around pipe threads. It is also popularly but incorrectly called Teflon tape.Thread seal tape lubricates allowing for a deeper seating of the threads, and it helps prevent the threads from seizing when being unscrewed. The tape also works as a deformable filler, helping to seal the joint without hardening or making it more difficult to tighten, and instead of making it easier to tighten.