PTFE Threadseal Tape for Water Pipes is malleable, deformable, & impermeable. STUK PTFE Tape 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.

One of the defining characteristics of PTFE is how good it is at defeating friction. The use of PTFE tape in tapered pipe threads performs a lubricating function, which more easily allows the threads to be screwed together, to the point of deformation, which is what creates the majority, if not all, of the seal.