Thread seal tape (also known as PTFE tape, Teflon tape or plumber's tape) is a polytetrafluoroethylene (PTFE) film tape commonly used in plumbing for sealing pipe threads. Thread seal tape lubricates allowing for a deeper seating of the threads and it helps prevent the threads from seizing when being unscrewed.
May cause Cancer and/or Reproductive Harm - www.P65Warnings.ca.gov