What is stopper?

A stopper is a small device used to block or prevent fluid flow in a container. It is typically made of rubber, cork, plastic, or glass. Stoppers are commonly used in scientific laboratories to seal test tubes, Erlenmeyer flasks, and other containers when conducting experiments. They are also used in the food and beverage industry to seal bottles and jars. Some stoppers are designed to be inserted and removed manually, while others are designed for longer-term use and require tools or equipment to install and remove. Stopper sizes and types vary depending on the application they are used for.