It's one of those things that isn't what it is called, but everyone calls it "Teflon Tape", you are more correct
But if you walk into a Hardware store or Parts store and ask for "Teflon Tape" they will know what you mean.
Thread Tape: is probably the most correct. But google "teflon tape" and you will get tons of hits on what you want, all called the wrong thing. Sometimes just easier to go with the flow.
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From Du Pont:
? Teflon? isn?t a thing ? it?s a brand! A world famous brand that?s owned by DuPont.
? The DuPont? Teflon? brand identifies products that are made with DuPont raw material(s), like fluoropolymer or industrial coatings. Over time, the tape has been mistakenly referred to as "Teflon tape". We thought it was important to let you know that.
? If somebody offers to sell you ?Teflon tape? when you need plumber tape (or thread seal tape), they are wrong, mistaken or ? worse ? trying to mislead you. To help you make an informed purchase, you should be aware that no plumber tape is authorized by DuPont to be sold as ?Teflon tape?.
? DuPont has brought thousands of meaningful innovations to people for more than 200 years, including many Teflon? branded products for consumers. Plumber tape is not one of these innovations.
Teflon? is a registered trademark of DuPont.