A mahogany box with two dials at the front protected by a glass panel. The dials are both graduated to indicate up to 15degs of inclination from the horizontal. One dial-plate is marked "ATHWARTSHIP" and the other "FOR & AFT". The mechanism consists of two pendulums suspended in a bath of oil, connected to pointers by gearing. Three bras brackets are attached to the back of the instrument for securing to ship.