A volumetric flask, also known as a “Jouget flask,” is a type of laboratory flask used for preparing solutions with a specific concentration and for maintaining an accurate volume at a specific temperature. These flasks are typically pear-shaped with a flat bottom and are made from glass or plastic in various colors. This type of flask has a long neck with a calibration line marked on it. Volumetric flasks are highly accurate and can only measure the volume indicated on them when used correctly. A plastic cap is designed for this type of flask to facilitate easy shaking and mixing of the solution during preparation. Glass volumetric flasks are generally colorless and are available in either simple or transparent forms, as well as amber-colored. The colored and amber types are used for light-sensitive compounds such as silver nitrate or vitamin A. Compared to flat-bottomed flasks, glass volumetric flasks have a narrower and longer neck.