Anemometer in a box. The main dial has three integral dials and a main indicator all controlled by a side mounted lock/unlock lever. The main dial is mounted on three brass pillars to the round base. The metal vanes rotate freely within a circular frame.

Used on sea trials of a ship to gauge wind speed thereby allowing corrections to be made to the measured speed of a ship through the water. Corrections for the operation of the object are on a label adhered to the inside of the lid. There are two adjusting keys housed in the box.