Before Dupont got all picky about their trademark, this product used to be called Teflon Tape.l

Rolls on dry and molds into pipe threads to form a leak-proof seal
1/2" x 43 ft roll

When appying remember to wrap in the same direction in which you would screw a nut onto the fitting, and to start at the opening of the fitting and wrap toward the body. This way the tape will not unwrap as you tightend the fitting.