The sextant is composed of circular polished brass plates with a lid that when screwed on the back of the instrument serves as the handle. The index arm is moved by a milled knob on the upper plate. The instrument has two index shades in green and red, which are moved by levers. The index glass is non-adjustable and the horizon glass is moved by square-headed screws with a milled key shipped in the upper plate.

Attached to the sextant is a single lens magnifier on a hinged 51mm swivelling arm. The telescope is 74 mm with an erect image and a red shaded eyepiece fitted in the body. It has a pinhole sight for use when the telescope is removed. A compass (diameter 32 mm), is fitted at the centre of the upper plate, graduated to points, and per quadrant in degrees. The compass is fitted with a stop mechanism and card filter, and two small sight vanes attached to the upper plate.

The instrument has an inlaid silver scale from -5° to 140° by 30 arcminutes, measuring to 120° (the digits are read from the pivot). The sextant has a silver vernier measuring to 1 arcminute, with zero at the left.

The sextant is contained in a fitted leather carrying case.

This combination of sextant and compass enables the observer to take a bearing and an angle of line simultaneously. Henry Swaisland provisionally patented this pocket sextant (no. 452 of 1859).