PTFE is a synthetic fluoropolymer of tetrafluoroethylene. It is hydrophobic and is used as a non-stick coating for pans and other cookware. It is very non-reactive and is often used in containers and pipework for reactive and corrosive chemicals. PTFE has excellent dielectric properties and a high melting temperature. It has low friction and can be used for applications where sliding action of parts is needed, such as plain bearings and gears. PTFE has a wide variety of other applications including coating bullets and use in medical and laboratory equipment. Given its many uses, which include everything from an additive to coatings, to its uses for gears, fasteners and more, it is, along with nylon, one of the most widely used polymers.