The quintant has a polished brass frame, with a detached wooden handle. The tangent screws and clamping screws are located on the back of the two index arms. The two index glasses are adjusted by screws and the two horizon glasses by screws and square-headed screws.

Attached to the instrument are two single lens magnifiers each on a 61mm swivelling arm. An L-shaped, non-adjustable, threaded telescope bracket is also fixed to the frame. The telescope is 115 mm in length with an inverted image. The quintant has no box.

The instrument has two polished brass limbs with inlaid silver scales both from -5° to 185° by 20 arcminutes, measuring to 150° (left) and 165° (right). The quintant has two silver verniers, both measuring to 20 arcminutes, with the zeros at the right and the left.

The quintant was designed to measure an angle on either side of an object in one observation.