Threa seal tape — commonly known as "Teflon tape", "PTFE tape" or "plumber's tape" — is a polytetrafluoroethylene (PTFE) film cut to specified widths for use in sealing pipe threads. The tape is wrapped around the exposed threads of a pipe before it is screwed into place. Since the PTFE is malleable, deformable and impermeable, it acts a little like putty under compression, being forced into small gaps between threads in order to create an air- and watertight seal when threaded into a joint. The tape is commonly used commercially in pressurized water systems, such as central heating systems, as well as in air compression equipment and thread joints with coarse threads.