The sextant consists of circular anodized brass plates with a detached wooden handle for attachment to the back of the instrument by bayonet fitting, and a plumb and line. The index arm is moved by a milled knob on the lower plate. The sextant has two green index shades and no horizon shades. It has two index glasses; one rigidly fixed, the other moved by the index arm. Index-glass adjustment is made by a key shipped in the wooden handle and on the horizon-glass, which is completely silvered, by a milled knob on the back of the instrument.

Attached to the sextant is a single lens magnifier on a 58mm swivelling arm. There is also a threaded telescope bracket that is non-adjustable. The telescope is 62 mm in length with an erect image.

The instrument has an inlaid silver scale from -5° to 205° by 30 arcminutes, measuring to 186° (the digits are read from the pivot). The sextant has a silver vernier measuring from 0 to 30 arcminutes, with zero at the left.

The sextant is contained in a fitted brown leather case with a carrying strap, lined with brown velvet, and containing in the lid a stamp for, ’J.H. Steward, 406 Strand London’, and marked on the outside, ‘AJW’.

The angle between the two index glasses may be increased up to 180°. This instrument can be used for reading vertical angles, and was primarily meant for use on land. According to the patent it could, for example, be used when setting out railway curves. J. H. Blakesley and J. H. Steward patented this pocket sextant (no. 9440 of 1893).