The sextant has a polished brass straight-bar frame and a wooden handle with a brass-lined threaded hole for a second handle or a stand. The tangent screw and clamping screw are positioned on the back of the index arm. The sextant has four shades, two red and two green, and three horizon shades, two green and one red. Index-glass adjustment is made by a screw and on the horizon glass by a capped milled knob.

Attached to the sextant is a magnifier travelling on a rack and pinion. There is also a threaded telescope bracket in two parts, fitted for correcting collimation error, with perpendicular adjustment by a rising-piece and a milled knob. The telescope is 126 mm in length with an inverted image, and four cross wires. A second telescope, sight-tube, magnifying glass, and a shaded eyepiece are missing. The sextant is contained in a polished keystone box, with a Kew Observatory certificate of examination (date illegible) in the lid, pasted over with a later handwritten note with the inscription on the instrument as given above.

The instrument has a polished brass scale from -2° to 137° by 10 arcminutes, measuring to 125°. The sextant has a brass vernier measuring to 10 arcseconds, with zero at the right.