AN5740 24H Night & Day

This version features a stainless-steel case and outer cover with a sapphire crystal.

We recreated the AN5740 Master Navigation Watch so it can be enjoyed as both a pocket watch and a wristwatch.

The original navigation pocket watch was used by the U.S. Army and Navy during World War II. In the designation “AN5740,” “A” stands for Army and “N” for Navy. Our dedicated outer case allows the watch to move between pocket and wrist use. The design is registered.

Wrapping a pocket watch in a leather wrist cover can make it bulky and conceal its original shape and character. Welding on lugs is simpler, but permanently changes its use as a pocket watch. Our approach preserves the pleasure of both forms.

The Night & Day dial recreates a rare design that our original account describes as scarcely surviving even among collectors. It is associated with a small number of pilots flying long-range strategic bombing missions. Its black-and-white 24-hour layout helps the wearer distinguish AM from PM intuitively.

To make the watch easier to wear on the wrist, we reduced the diameter by approximately 5 mm to 46 mm. This version uses a battery-powered quartz movement. The large dial helps keep the 24-hour display easy to read.

The meaning of “B.J.B.” on the dial remains uncertain. One theory connects it with “Berlin-Japan Bomber” and strategic bombing units; it should be treated as a theory, not an established explanation.

Product specifications — AN5740 24H Night & Day

Movement: Swiss Ronda 24-hour quartz movement. Accuracy at room temperature: 15 seconds per month (reference value).

Case: Stainless steel.

Battery: Silver-oxide SR920SW. Approximate battery life: 2 years.

Water resistance: 3 ATM. For everyday use; not a deep-water diving watch.

Crystal: Domed sapphire crystal.

Case dimensions: 46 mm wide × 56 mm long × 16 mm thick.

Outer cover: Stainless steel. Shipping is currently paused. This preview does not accept orders.