Narrow-Mouth Bottles, PTFE PFA, PTFE PFA screw closure The most temperature-resistant, chemical-resistant, corrosion-resistant containers available. PTFE PFA is inert to virtually all chemicals except molten alkali metals, fluorine at elevated temperatures and certain complex halogenated compounds at elevated temperatures and pressures. Bottles with closure withstand temperatures from -270° to 250°C. Translucent bottles allow liquid levels to be seen. Linerless, Leakproof† closure made of PTFE PFA for a positive seal. Packaged individually. Autoclavable/Leakproof† NOTE: Before autoclaving, just set cap or closure on top of the container without engaging the threads.