PTFE (polytetrafluoroethylene or Teflon) O-rings are a type of seal commonly used in high-temperature and chemical-resistant applications. These O-rings are made from a synthetic fluoropolymer called PTFE, which is known for its exceptional chemical resistance and extremely low coefficient of friction. PTFE O-rings are highly resistant to almost all chemicals, including acids, bases, and solvents, as well as high temperatures. They are also resistant to abrasion and wear, and have a very low compression set. They are can be used in applications such as chemical processing, aerospace, and semiconductor manufacturing.