The sextant is composed of semi-circular polished brass plates with on one side a sliding shutter, and on the other side a hinged plate. The index arm is moved along a tangent screw by a detached milled key shipped in the upper plate. The sextant has two index shades, in red and orange, operated by brass studs moving in slots cut in the lower plate. There are no horizon shades. Index- and horizon-glass adjustment is made by screws. Attached to the sextant is a single lens magnifier on a 51mm swivelling arm. The telescope is 26 mm in length with an erect image and a red shaded eyepiece fitted in the body. The sextant has no box.

The instrument has a brass scale from -2° to 106° by 30 arcminutes, measuring to 89° (the digits are read from the pivot). The sextant has a brass vernier measuring to 10 arcseconds, with zero at the left.