What Is Plumbing Tape? 

Plumbing tape (PTFE or thread seal tape) is a thin film wrapped around threaded pipe connections to fill small gaps and prevent leaks. 

Wrap this tape around male pipe threads before tightening. It is ideal for shower arms and threaded adapters.

It is not a repair patch. Never wrap it outside a cracked pipe, and avoid using it on compression or gasketed fittings.

Always wrap the tape in the same direction the fitting tightens to prevent it from unraveling.

It is commonly known as PTFE tape, thread seal tape, or plumber's tape. 

It helps seal threaded joints, but it is never a permanent fix for a cracked or damaged pipe.