Gauged flasks are containers 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 heels and have a volume marking and possibly a closure. They are usually pear-shaped and have a flat bottom, and they are made of glass or plastic. A single engraved annular graduation on the elongated, narrow necks of the bottles indicates the volume contained when the bottle is filled to that point. This indicates that the bottle has been sized “to contain”.