Abstract: A precision measuring device for accurately measuring large volumes of liquids which includes a primary measuring vessel having a predetermined overflow level together with an overflow saver vessel for the purpose of catching and saving any liquid above the desired measured amount. Primary valve means at the bottom of the primary measuring vessel allows for easy and complete discharge of said primary vessel after the measuring process takes place while a secondary valve between the overflow saver vessel and the primary vessel permits any excess liquid which has overflowed from the primary vessel into the saver vessel to be emptied into the primary vessel at the beginning of the next measuring operation. An additional displacement structure is also employed to permit accurate changes in measured amounts within the primary vessel. The primary vessel is also mounted on trunnions to permit rapid dumping of the measured contents when so desired.