The octant has a polished brass strait-bar pattern frame with a black plastic handle. The white plastic micrometer drum and pressure clamp are located at the bottom of the index arm. The octant has four green shades and three green horizon shades. Index-glass adjustment is made by a screw and on the horizon glass by capstan screws. Attached to the octant is a telescope bracket without adjustment. The fixed telescope is 39 mm is length, with a rubber eyecup. Accompanying the octant is an adjusting pin and a bottle for lubricating oil. The octant is contained in a square fitted Bakelite box, with a Huson, Henry Hughes and Son Ltd certificate of examination in the lid, dated 27 November 1943.

The instrument has a polished brass limb with inlaid silver scale from -5° to 120° by 1°, measuring to 100°. Micrometer to 1 arcminute