Military Field is a specific corner of the field-watch world: not just civilian pieces in earth tones, but watches built to actual military procurement specifications or following them to the letter. The lineage is concrete. In 1942 the US Army's A-11 spec had Bulova, Elgin and Waltham producing legible, robust watches accurate to roughly +/- 30 seconds a day. For British forces in 1944 and 1945, twelve Swiss makers (Buren, Cyma, Eterna, Grana, Jaeger-LeCoultre, Lemania, Longines, IWC, Omega, Record, Timor and Vertex) supplied what later became the Dirty Dozen: black dial, Arabic numerals, small seconds at six, a railroad minute track and a WWW (Watch, Wrist, Waterproof) caseback stamp. The American thread continued with MIL-W-46374, first published 30 October 1964, which codified fixed lugs, tritium lume and pared-down legibility; the 1976 B revision added the radiation symbol to the dial.
The brand carrying this niche most literally today is Marathon. The Canadian firm has supplied Allied forces since 1941 and still holds active military contracts. Its General Purpose Mechanical (GPM) is built to MIL-PRF-46374G Type II: a 34mm high-impact composite Fibreshell case, tritium gas tubes that glow without needing prior light, around $525. The Hamilton Khaki Field Mechanical 38mm is a direct descendant of old US-issue watches, with the hand-wound H-50 caliber and up to 80 hours of reserve, roughly $595 in steel and $895 in bronze. For a more period-faithful feel there is the Praesidus A-11 (NH35 automatic, assembled in the USA), or the Swiss-made Vertex M100, a nod to the brand's own Dirty Dozen heritage. And if you want a genuinely issued watch, the CWC G10 has been produced under MoD contract since 1980.
Before buying, decide which you actually want: the Military Field aesthetic, or real issued DNA. They lead different ways. For the look, Hamilton is hard to beat on value. For real tritium and a live contract, Marathon. Fixed lug bars are tough but make strap changes a chore, so go in knowing that. On crystals, sapphire shrugs off scratches far better than acrylic, but acrylic flexes rather than shatters on impact and suits vintage accuracy. A 12/24 dial helps you read military time, though the inner 24-hour ring can look busy. Sizes of 34 to 38mm are the historically correct range; 42mm and up wears easier on a modern wrist but is not period.
Who it suits: anyone who wants a plain, mission-focused watch with nothing to prove. Even within the niche there is a split. You will choose between full vintage accuracy (acrylic, fixed lugs, a small case) and daily practicality (sapphire, quick-change straps, 100m). Quartz issue like the CWC G10 gives maintenance-free precision; mechanical issue like the Hamilton or Marathon GPM keeps the watchmaking soul. There is no wrong pick, only the right one for your intent.