The reflecting circle consists of a circular polished brass frame, with a wooden handle. A detached U-shaped bracket holds a second handle with a brass-lined threaded hole for a third handle, which can also be screwed on the front of the frame. The instrument has three rigidly connected index arms on the back of the frame, with a double-ended tangent screw at the bottom and a clamping screw on the back of one of the arms. It has three shades, two 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 a screw and a capstan screw.

Attached to the circle are two hinged magnifiers on 65mm swivelling arms, a third detached magnifier is missing. There is also a threaded telescope bracket with perpendicular adjustment made by a rising-piece and a milled collar. The telescope is 68 mm in length with an inverted image and four cross wires. A second telescope is 85 mm long with an erect image. Accompanying the instrument is a sight-tube, which is 130 mm in length, two red shaded eyepieces, an adjusting key, and an adjusting pin.

The instrument has a polished brass limb with an inlaid silver scale from indicated 160° to 0° to 160° although the entire circle is divided by 20 arcminutes. The reflecting circle has three silver verniers, which read to 20 arcseconds, with the zeros at the left.

The reflecting circle is contained in a square fitted wooden box, with trade labels in the lid for Troughton, 136 Fleet Street, London (1788-1804); for William Gerrard, 35 South Castle Street, Liverpool (1862-90); for Dawson and Melling, Liverpool (1837-39), and for W. Jewitt and Co (successors to Melling and Co), 39 Castle Street, Liverpool (1847- after 1851). There is also an oval handwritten label, ‘A Bulmer Mill Turner 1907’. Each maker's label was presumably added to the box when the reflecting circle was taken in for servicing or repairs, and so the labels indicate the long working life of this particular instrument.

The reflecting circles produced by Edward Troughton from 1796, like this example, characteristically had three index arms with verniers on each, allowing an average of three different readings to be taken for improved accuracy. The U-shaped bracket was recommended by Mendoza Rios, and according to him first applied by Troughton.