The sextant has an anodized brass oval-pattern frame and a wooden handle. The tangent crew and clamping screw are positioned on the back of the index arm. The instrument has four shades, three red and one green, and three horizon shades, one red and two grey. Index-glass adjustment is made by a screw and on the horizon-glass by capstan screws.

Attached to the sextant is a magnifier on a 93mm swivelling arm. There is also a threaded telescope bracket in two parts, fitted for correcting collimation error. It has perpendicular adjustment made by a rising-piece and a milled knob. The telescope is 183 mm in length with an inverted image and four cross wires. A second telescope is 83 mm with an erect image. The sight-tube is 81 mm in length and has a red shaded eyepiece, a spare clamping screw for the index arm, which is a later addition, and an adjusting pin, which is now missing.

The instrument has a polished brass limb with an inlaid silver scale from -5° to 160° by 15 arcminutes, measuring to 134°. The sextant has a silver vernier measuring to 15 arcseconds, with zero at the right.

The sextant is contained in a keystone box, with a trade label in the lid for John Cail, Newcastle-on-Tyne, a rubber stamp and pencil notes, which are both illegible.