An aspirating pipette, sometimes called an aspiration pipette, is a transparent non-calibrated, non-graduated pipette used in laboratories, classrooms, and research facilities to transfer and mix liquids when volume measurement is not required. Pipette aspiration is performed with an aspirator device or vacuum to remove the contents from laboratory containers to facilitate safe disposal. Glass aspiration pipettes are used with solutions that are corrosive to polystyrene, and can be sterilized for reuse. Polystyrene aspirating pipets are designed for single-use and reduce the risk of breakage when used with mechanical vacuum aspirators. Features to consider when selecting aspirating pipettes include the length of the pipette required for vessel depth, capacity, the method of aspiration, and pipette material.