Pre-slit PTFE/Silicone septa have a working temperature range from -40 degrees C to 200 degrees C. The chemical compatibility of the septum is that of silicone, but it does not have PTFE chemical resistance like a septum that is not pre-slit. LCMS Certified Clear Glass 12 x 32 mm Screw Neck Max Recovery Vial, with Cap and Preslit PTFE/Silicone