The sextant has an anodized brass diamond-pattern frame with a protective frame over the fittings and mounts. It also has a wooden handle. The tangent screw and clamping screw are positioned on the back of the index arm. The sextant has four shades, three red and one green, and three horizon shades, two red and one green. Index-glass adjustment is made by a screw and on the horizon glass by capstan screws. Attached to the sextant is a magnifier travelling on a worm screw with a milled knob. There is also a threaded telescope bracket with perpendicular adjustment made by a rising-piece and a milled knob. The telescope is 135 mm in length with an inverted image and four cross wires. A second telescope is 178 mm with an inverted image and four cross wires. It has a rotating shaded eyepiece with three shades, two red and one green. The sight-tube is 92 mm in length and has an adjusting pin. The sextant is contained in a mahogany keystone box, with a trade label in the lid for W. C. Cox, 87 Fore Street, Devonport (1851), stuck over a trade label for George Stebbing (died 1846), High Street, Portsmouth, in which he announces that his son George James Stebbing was continuing the business.

The instrument has a polished brass limb with inlaid silver scale from -2° to 136° by 5 arcminutes, measuring to 121°. The sextant has a silver vernier measuring to 20 arcseconds, with zero at the right.