The Marathon General Purpose Mechanical (GPM), reference WW194003BK-0001, is what a field watch looks like when it is built to an actual government specification rather than borrowed from one. This 34mm automatic wears a dial that reads "U.S. Government," the same marking carried by watches supplied for official use.

Marathon has been making military timepieces since its first order from the Royal Canadian Air Force in 1941, and the GPM is produced to MIL-PRF-46374G, Type II, Class 4, a standard that traces back to the GG-W-113 field watch spec of the 1960s. The U.S. Government dial is matched by government markings on the caseback, so this is the version for anyone who wants the issued article rather than a civilian lookalike. A black composite fibreshell case keeps the whole package light and low-glare, while tritium tubes on the hour markers and hands glow all night without ever needing a light source to charge them.

Inside is a 24-jewel automatic movement (NH35-based) that winds itself as you move and can also be wound by hand through the pressure crown, with roughly 41 hours of reserve. Sapphire crystal protects the dial and its 12- and 24-hour scales, and a black one-piece nylon strap (10 inches) finishes it in proper issue fashion.

Marathon GPM WW194003BK-0001 Specifications

• Reference: WW194003BK-0001, General Purpose Mechanical
• Case: 34mm black composite fibreshell, 12.5mm thick, 41mm lug to lug
• Movement: automatic with hand-winding (NH35-based), 24 jewels, approx. 41-hour reserve
• Water resistance: 3 ATM
• Crystal: sapphire; pressure crown
• Lume: tritium gas tubes on hour markers and hands
• Dial: matte black with U.S. Government marking, 12- and 24-hour scales
• Strap: black one-piece nylon, 10 inches, 16mm lugs

Built to spec, marked for service, and ready for daily wear.