Long days call for a watch you can forget about until you need it. The Marathon GPM in sage green, reference WW194003SG-0006, uses a lightweight composite case and a 34mm footprint so it disappears on the wrist, then delivers a clear, tritium-lit read the moment you glance down.

That comfort comes from the fibreshell case, a composite that is far lighter than steel and does not get cold against the skin in winter or hot in summer sun. It is finished in sage green, a calm, slightly grey green, and fitted with a matching 11-inch DefStan nylon strap whose extra length works over a sleeve or on a larger wrist. The black dial reads "U.S. Government" and carries 12- and 24-hour scales, with tritium tubes that glow continuously, no charging required.

Under the hood is a 24-jewel automatic (NH35-based) that winds itself through wrist movement and can be hand-wound at the crown, with about 41 hours in reserve. The watch is made to MIL-PRF-46374G, Type II, Class 4, the specification that defines how a modern general-purpose military watch should perform. Sapphire crystal guards against scratches from rock, brush and toolbox alike.

Specifications: WW194003SG-0006

• Marathon General Purpose Mechanical (GPM), U.S. Government dial
• Sage green composite fibreshell case, 34mm, 12.5mm thick, 41mm L2L
• Automatic with hand-winding, NH35-based, 24 jewels, ~41h
• 3 ATM water resistance
• Sapphire crystal; pressure crown
• Tritium illumination on hour markers and hands
• Sage green DefStan nylon strap, 11-inch, 16mm lugs

Light enough for all day, rugged enough for whatever the day brings.