This octant measures 11-1/4 inches from top to bottom. It is fully functional but has some damage on the back of the unit and is missing two brass support feet and a small ivory inset that was probably used to record navigation reading with a lead pencil. It was manufactured by Spencer, Browing and Co., London in the 1790 - 1830 time frame. The wooden case is in pretty rough shape and has a label inside from a New York Co. who were sellers of marine instrumentation.