40 ml (10 dram) Amber glass vials, black pp cap & PTFE disc. Amber vials offer protection from harmful light and uv rays for light sensitive products. Made of type i borosilicate glass, providing exceptional resistance to heat shock and chemical leaching. The glass is non-porous and has no catalytic affect. Because the boron oxide particles in the glass are so small, the silicate is held more closely together, resulting in a much stronger glass for your laboratory needs. Attached 24-400 polypropylene caps with .015 in PTFE disc offer excellent chemical compatibility. The PTFE disc is chemically inert and heat resistant. polypropylene caps are known for impact strength, cost effectiveness, and pliability.