A Pasteur pipette, also known as a dropper or plastic transfer pipette, is a laboratory tool used for transferring small volumes of liquids. It is typically made of glass or plastic and has a thin, elongated shape with a tapered tip.

There are two primary types of Pasteur pipettes: glass and plastic. Glass pipettes are more durable and can be autoclaved for sterilization, while plastic pipettes are disposable and often used for applications where contamination is a concern.

To use a Pasteur pipette, you squeeze the bulb (or plastic part) to create a vacuum, immerse the tip in the liquid, and slowly release the bulb to draw in the liquid. Then, you can transfer the liquid by gently squeezing the bulb again.

Pasteur pipettes are used for a wide range of laboratory tasks, including transferring small volumes of reagents, mixing solutions, and collecting or dispensing biological samples, such as blood or cell cultures.

Glass Pasteur pipettes can be sterilized by autoclaving at high temperatures. However, plastic Pasteur pipettes are typically disposable and not suitable for autoclaving.