Manufacturers of High Quality Military Watches Since 1974

MWC "Depthmaster" 100atm / 3,280ft / 1000m Water Resistant Military Divers Watch in Stainless Steel Case with Helium Valve (Quartz)

£349.00 GBP


Product Details

SKU: 100AT/12/SS/QZ/ST

This model in both PVD and Stainless Steel versions is now sold out and discontinued. It was made for a procurement company that secured a contract to supply a watch with this particular specification, which differs in some ways from our other 100ATM watches. Most of the additional requirements specified for the contract are outlined below.

MWC "Depthmaster" Military Diver Model

The MWC "Depthmaster" Military Diver models are MWC's latest heavy-duty range. These watches are extremely robust, featuring a sapphire crystal and a 100atm water resistance rating, making them suitable for diving with mixed gases at extreme depths. They also come with a wider 24mm strap (most military diver watches use a 20mm strap) and a non-scratch ceramic bezel, which is easier to grip in extreme cold. These watches are specifically designed for professional divers operating under very challenging conditions.

Helium Escape Valve

All MWC 100ATM models are fitted with a helium escape valve. People often ask how helium gets into a dive watch. Essentially, a helium molecule is among the smallest of all molecules. Because they are so small, even though the seals keep water out, helium molecules can still enter the watch.

Professional users of watches with helium escape valves are saturation divers who spend long periods at great depths under high pressure. Helium molecules can build up inside the watch, creating pressure that can damage the watch or blow out the crystal or crown. This is extremely dangerous if you are checking or resetting the time. The helium escape valve allows the helium molecules to escape during decompression when the watch returns to normal sea level pressure. The valve is one-way, letting helium out but preventing anything external from getting in.

Why Helium Is Important in Deep Diving

Helium is used in deep-sea mixed gas diving because it does not have the negative effects of nitrogen, such as nitrogen narcosis. Consequently, helium replaces nitrogen in most deep-sea mixed gas diving applications.

Professional divers can operate at great depths for extended periods, living in dry environments pressurized with an oxygen/helium mix. When they surface and decompress, this gas must be removed to prevent problems like the crystal or crown being blown out, which can potentially injure or even blind someone.

Special Features of This Model

While this watch is similar to our other 100ATM models, it was produced specifically for a military procurement contract. The contractor specified that the watch should maintain high accuracy at altitudes up to 12,000m / 40,000ft without compensatory pressurization and be resistant to magnetic fields up to 4,800 A/m (about 60 gauss). These demanding specifications make this watch slightly different from other models in the 100ATM range. Additionally, the contract required the watches to be unbranded with a sterile dial.


  • Movement: Swiss Ronda 715li with a 10-year battery life and hacking function
  • Water Resistance: 100atm / 3,280ft / 1000m
  • Crown: Screw-down locking
  • Helium Escape Valve: Yes
  • Dimensions:
    • Width: Including Crown 47mm (Excluding Crown 44mm)
    • Thickness: 18mm
    • Crystal Diameter: 31mm
    • Lug to Lug: 48mm
    • Weight: 132g
  • Bezel: Unidirectional non-reflective with ceramic insert
  • Crystal Type: Sapphire with Anti-Reflective Coating*
  • Case: 316L Stainless Steel
  • Illumination: Luminova on markers, hands, and bezel
  • Strap: 24mm NATO Webbing Strap (1 x Black and 1 x Grey)

Benefits of Sapphire Crystal

Synthetic sapphire is the best material for watch crystals due to its strength and shatter and scratch resistance. These characteristics make it highly appealing to military and security personnel, police officers, and those who lead active outdoor lifestyles. These groups account for over 70% of our customers. Over 90% of cracked crystal incidents involve watches with mineral glass crystals. Even hardened mineral crystals do not match sapphire's durability under adverse conditions. Sapphire crystals are heat-treated to remove internal stresses, enhancing their strength, and are made with two layers of anti-reflective coating. While sapphire crystal is more expensive, it is typically fitted to higher-end watches and is now used in the latest iPhone models.

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