PTFE (polytetrafluoroethylene), a thermoplastic fluoropolymer known as Teflon®, produces solid O-rings prized for near-universal chemical inertness, resisting almost all acids, bases, solvents, oils, and gases. These typically white seals excel in extreme temperatures (-200°C to +260°C), offer ultra-low friction, superior electrical and thermal insulation, and virtually unlimited shelf life. Suited for static sealing in chemical processing, pharmaceuticals, food & beverage, and aerospace, pure PTFE O-rings lack the elasticity of elastomers, restricting them from dynamic or high compression uses.