Combine the excellent chemical resistance of PTFE FEP with the convenience of a ETFE screw closure. They're unbreakable, nearly transparent, non-contaminating, and resist virtually all chemicals. Withstand temperatures from -270¡C to +205¡C; closures from -100¡C to +150¡C. Can be autoclaved or chemically sterilized repeatedly. Before autoclaving, just set cap or closure on top of the container without engaging the threads. Useful with all organic solvents, concentrated oxidizing agents. Can be boiled in concentrated nitric acid for trace metal work.