Volumetric Flasks, Narrow Mouth, Class A, As Per USP Standards

Volumetric flasks are vessels that have been calibrated to hold and measure a specific amount of liquid at a specific temperature. They can be used to make dilutions and standards and have a volume marking and possibly closure. They're usually pear-shaped and have a flat bottom, and they're made of glass or plastic. A single engraved ring graduation mark on the flasks' elongated and narrow necks denotes the volume contained when the flask is filled to that point. This indicates that the flask has been calibrated "to contain."