Teflon tape is a very thin white tape used to wrap the threaded ends of pipes to improve the watertightness of a joint, there is also a another variety of thread seal tape that is pink. The pink tape which is thicker so you need less to obtain the same thickness as white.

People often ask the following questions about the use of Teflon tape

How much Teflon tape should I use?
How many times around should I wrap Teflon tape?
Which direction should Teflon tape be wrapped?

• Start wrapping the male threads at end of the pipe but do not lap over the end. Doing so may result in reduced water pressure or even clogs from bits of the tape that get into the water supply.
• Start with a couple loops around at the end, then wrap all the threads, overlapping half the width of the tape on each wind.
• Wrap in the direction of the threads starting from the end and proceeding toward the length of the pipe. Wrapping the wrong way may result in the tape coming unwound as the fittings are tightened.
• As you wrap, keep tension on the tape so that it is pulled into the threads.
• If you loosen or disconnect a fitting, remove the old tape and rewrap with a fresh piece.