Stoppers are an essential part of many laboratory vials. They provide an air-tight seal that not only keeps the contents in the container intact, but also protects them from contamination. Stoppers come in a variety of materials and sizes to fit different types of vials. One and two piece natural polyethylene stoppers are commonly used to create air-tight seals with display vials and some patent lip and shell vials. They are durable, chemically resistant, and can withstand temperatures up to 140°F (60°C). Natural polyethylene stoppers also provide superior seal integrity, making them an ideal choice for many laboratory applications.