Graduations-Semicircle graduated 0-180, 180-0. The alidade 5.8" (14.7cm) long has a vernier scale at each end, graduated 0-60, to 30'. There is a straight edge 7.25" (18.5 cm) long at the lower part of instrument. A ball and socket head and a plate 2.6" x 2.3" (6.5 x 5.8 cm) are attached to back of instrument.
Sights-Two sight vanes 1.6" (4 cm) long mounted on straight edge, one sight with a vertical slit with a rectangular aperture above (complete with thread), the other with a rectangular aperture (no thread) with a vertical slit above. Two sight vanes 1.6" (4cm) long mounted on alidade, one sight with a vertical slit with a rectangular aperture above (no thread), the other with a rectangular aperture (no thread) with a vertical slit above.
Compass- Dia. 1.75" (4.5 cm) mounted at centre of instrument. Fitted with a tapered flat bar needle 1.4" (3.5cm) long, with a brass pivot cap at centre. Graduated to 16 points and quadrantally in degrees.