MWC "Depthmaster" 100atm / 3,280ft / 1000m Water Resistant Military Divers Watch in a Stainless Steel Case with GTLS and Helium Valve (10 Year Battery Life)
MWC "Depthmaster" 100atm / 3,280ft / 1000m Water Resistant Military Divers Watch in a Stainless Steel Case with GTLS and Helium Valve (10 Year Battery Life)
The MWC Depthmaster is the toughest diver’s watch in our lineup, built for extreme environments and professional use. With a water resistance rating of 100ATM (1,000m / 3,280ft), a sapphire crystal, and a ceramic bezel, this model is designed for mixed-gas diving at great depths and harsh conditions.
Unlike most military divers’ watches that use a 20mm strap, the Depthmaster comes with a wider 24mm NATO strap for extra strength and stability. Illumination is provided by tritium GTLS tubes on the hands and markers, ensuring constant visibility in low-light or nighttime operations.
Helium Escape Valve
All Depthmaster 100ATM models are fitted with a helium escape valve (HEV).
Why it’s needed: Helium molecules are so small they can penetrate watch seals during saturation diving, even when water and other gases cannot.
The risk: Without a valve, helium pressure builds up inside the watch. On decompression, this can blow out the crystal or crown—dangerous for the diver and catastrophic for the watch.
How it works: The HEV automatically releases helium during decompression, preventing damage while keeping water and debris out.
Most recreational divers won’t need this feature, but for saturation divers operating in pressurised helium/oxygen environments for days or weeks, it’s essential. A 100ATM diver’s watch would not be considered “fit for purpose” without it.
Why Helium for Diving?
Nitrogen causes narcosis at depth, which is why helium replaces nitrogen in mixed-gas diving. Helium avoids these effects, but it does find its way into watch cases—hence the need for HEVs.
Movement
Swiss Ronda 715Li quartz
10-year battery life
Hacking function for precise synchronization
Dimensions & Specifications
Movement: Swiss Ronda 715Li Quartz, 10-Year Battery Life
Synthetic sapphire is the gold standard for watch crystals:
Highly scratch and shatter resistant (far superior to mineral glass, even hardened versions)
Heat-treated to remove internal stresses and increase strength
Anti-reflective coated for clarity
Used by military, law enforcement, and outdoor professionals—groups that make up over 70% of our customers.
To put it into perspective: over 90% of cracked crystals we see are mineral glass. Sapphire virtually eliminates that issue, which is why it’s standard on the Depthmaster and increasingly found in premium electronics like the latest iPhones.
