A soldier might require a glow-in-the-dark watch dial for legibility while for others it might simply elicit a childlike sense of wonder. The most common way for watchmakers to achieve this effect without the use of batteries or electricity is with luminescent paint, colloquially called lume — but it's not the only option.
Modern lume needs to be “charged” by absorbing light from an external source and then will proceed to glow for a number of hours. An alternative approach toward creating luminescence makes use of tiny glass tubes filled with tritium gas which glow constantly and autonomously for years, but only a handful of watch companies regularly employ this interesting technology.
Tritium gas tube illumination was pioneered and developed by the Swiss company MB Microtec, which not only makes its own watches under the brand Traser, but also supplies other companies with these glowing tubes. Other uses for this tech include emergency exit signs and gun sights. Tritium is radioactive, but not at all harmful in the form or quantities found in watches today.
Compared to conventional luminescent paint, tritium has some benefits and drawbacks. Unlike, say, Super-LumiNova, which is brightest directly after being charged and then fades significantly over the following hours (its quality, brightness, and longevity depend upon a number of factors), tritium glows steadily and consistently. However, tritium gas tubes have a half life of 12 years and will need to be replaced after roughly 24 years (modern lume such as Super LumiNova doesn’t last forever, either). Tritium glows less brightly than many lume applications at full charge, but will often be brighter within the first hour as the lume fades.
Many watches use modern lume and tritium side by side with some colorful results, and the five light-show-on-your-wrist watches below — many of a tactical or military nature — are representative of the best brands specifically known for their use of tritium illumination.
Other watch brands that use tritium, it’s safe to say, are not making this specialized product in-house. Traser, however, is unique as a watch brand owned by the Swiss company MB Microtec that produces and supplies much of the watch industry with these tiny glowing tubes. Traser has also provided watches to the US and other militaries. Its 46mm-wide P68 Pathfinder has a Swiss automatic movement and is something of a light show in the dark with both Super LumiNova and tritium.
Ball Watch Co. is probably the brand that is best known for its use of tritium — and the company likes to lay it on thick. Whereas other brands use tritium primarily to reinforce legibility, Ball makes it a design centerpiece and brand signature. The Engineer III Marvelight watch shown here, for example, features 27 of these tubes between its hands and dial, but it's also an unusually bright colorful affair for a tool watch (though more monochromatic options are also available).
Marathon is known as a function-first tool and military watch brand, and tritium illumination is a core element across its lineup. If you want a legitimate tactical watch, Marathon has a claim to that designation, and has a steady track record supplying various governments with combat-ready wrist gear. The brand offers practical mechanical watches as well as affordable quartz options, but the simple field watch style of the plainly named General Purpose Mechanical hits all the right notes.
Luminox, as its name suggests, has a focus on nighttime legibility, often using both lume and tritium. The brand concept is built around tough military watches with land, sea, and air collections, as well as a mix of quartz and mechanical options. The quartz-powered Original Navy SEAL 3001 watch has the brand’s signature look and approachable price point. With tritium as its sole illumination, it will remain stealthy but readable in all lighting situations.
This company's name hints that it places emphasis on low-light visibility. The British brand Nite offers a range of sporty quartz watches often with a military theme — and tritium features prominently in all of them. Nite watches also tend to be relatively affordable, and the MX10 has a Swiss Ronda quartz movement and sleek field watch look with its 39mm case in black PVD.