We provide the protection of PTFE and the resealing ability of silicone with our septa and seals to fit our autosampler crimp top vials. This seal includes a two sided PTFE septa with silicone in the center. Caps are made of high quality polypropylene, Caps have the profile of a crimp or snap closure for compatibility with robotic autosamplers, Pre-assembled septa reduces the chance of contamination during sample preparation, while saving sample preparation time in the lab.