A mahogany deck box fitted with two brass hinges and a simple pressed brass clip-type catch; the top is glazed with a circular 'porthole' on the upper surface. The box is lined with grey imitation leather in the lid and lower half, shaped to the form of the watch. The lid has an open-ended clear plastic cover on the inside to hold an issue card, and the recess in the lower half, above the watch, contains a black-painted aluminium label. The label is marked in silver 'MINISTRY OF DEFENCE / HYDROGRAPHIC DEPT. / WATCH DECK / Stores Ref. H.S.527-3637 / Serial No. 1759'. The serial number is engraved through the surface to bright metal.

The bottom of the box is also covered with grey imitation leather. The chromium-plated nickel, open-face case has the winding/setting crown inset into a wide pendant, with a flat, shaped bow. Pulling out the winding button stops the watch (light spring against the balance) and engages the handset facility. The convex 'unbreakable' glass is held in a screw-down, knurled, chromium-plated nickel bezel. The nickel, screw-down back is machine engraved on the back 'NAVIGATION / MASTER WATCH / MFR'S PART NO.3992B / ­ SERIAL NO.1759-1942 / HAMILTON WATCH CO. / H.S.3'. The inside of the back is stamped with the case manufacturer's mark 'KEYSTONE', and 'CO' in a shield, 'BASE METAL' and '570499'.

A white enamel dial of 43 mm Æ is marked with the Government broad arrow above the centre, and signed 'HAMILTON' below. The dial has vertical Arabic numerals and small vertical Arabic five-minute figures. Polished and blackened steel spade and poker-hands have a counter-balanced blued-steel centre seconds hand.

The going barrel, barred movement is of bright, damascened, nickel, and is signed with black-enamel-filled engraving on the barrel bridge 'HAMILTON / WATCH CO. / U.S.A', and 'ADJ. TEMP. / AND 6 / POSITIONS'. The escape/fourth wheel bridge is marked '3992 B / 22 JEWELS / U.S. GOVT.'. It is also marked on the main plate, by the balance cock foot '3C1823'. A polished steel index, mounted on the balance cock, acts on a lateral screw for fine rating adjustment. The index has a scale under it, engraved with 'F' and 'S' for fast and slow. There is a four-wheel train with a centre seconds drive off the third wheel and a going barrel.

There is a double roller, jewelled and club tooth lever escapement. The impulse roller has a clear jewelled impulse pin and pallets with clear stones. The pallets bank against brass banking pins. The uncut balance is mounted with 20 brass screws around the rim. The flat spiral, 'Hamilton Elinvar Extra' balance spring, with over coil, has an index mounted on the upper surface of the balance cock. The train is jewelled to the centre (22 jewels in total) with red stones in brass press-in settings. The balance and escape wheel have end stones.

The instrument is in fine, almost as new condition, with a few slight knocks to the wooden box.

The serial number on the box and case (1759) should be the same as Hamilton's serial number for this '3C' calibre movement (i.e. 3C1759). The fact that the movement is serial number 1823 is almost certainly as a result of movements (all interchangeable with Hamilton material) becoming switched during overhauls at the MoD workshops.