The serological pipette is frequently used in the laboratory for transferring milliliter volumes of liquid, from less than 1 ml to up to 50 ml. The pipettes can be sterile, plastic, and disposable or sterilizable, glass and reusable. Both kinds of pipettes use a pipet-aid, for the aspiration and dispensation of liquids. Different sizes of pipettes can be used with the same pipet-aid for a variety of experimental assays. For example, serological pipettes are useful for mixing chemical solutions or cell suspensions, transferring liquids between receptacles, or carefully layering reagents of different densities. With careful attention to the level of liquid being aspirated and dispensed, serological pipettes can be useful tools for transferring accurate milliliter volumes of solutions in the lab. This video discusses the way that volume can be read on a serological pipette, how a pipet aid works, and many different applications for using a serological pipette.