MWC "Depthmaster" 100atm / 3,280ft / 1000m Water Resistant Military Di

We managed to secure a small quantity of these watches which were contract surplus overruns. They are all brand new, and in their boxes but most of the boxes have labels relating to the contract although a few do not, the watch is now out of stock on the manufacturers website but as you can see in the final image was originally sold at $425 on the US website and £349 on the UK site so at half price, these are a bargain for the watch with such a high specifications. We spoke to MWC, who confirmed that these watches were a once off production run so will not be made again in future with the same exact specification which, as you can see at the bottom of the description was very exacting.

>>> This Listing is Located in the UK <<<

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

The MWC "Depthmaster" Military Diver models represent MWC's latest heavy-duty range. These watches are exceptionally robust, featuring a sapphire crystal and a 100ATM water resistance rating, making them suitable for extreme-depth diving with mixed gases. They also come with a wider 24mm strap (most military diver watches use a 20mm strap) and a non-scratch ceramic bezel, which provides superior grip in extreme cold. Designed specifically for professional divers, these watches are built to withstand the most challenging conditions.

Helium Escape Valve & Deep-Sea Diving

All MWC 100ATM models are equipped with a helium escape valve. Many people ask how helium enters a dive watch in the first place. The answer is simple: helium molecules are among the smallest of all molecules. While the watch's seals effectively prevent water from entering, helium molecules can still pass through, even though other gases and liquids cannot.

The primary users of watches with helium escape valves are saturation divers. These divers spend extended periods at great depths under high pressure. Over time, helium molecules can accumulate inside the watch, creating internal pressure that may cause significant damage. This pressure can even blow out the crystal or crown when unscrewed, which is extremely dangerous, especially if a diver is simply checking or resetting the time. In severe cases, it can render the watch unusable.

The helium escape valve functions automatically during decompression, allowing helium to exit the watch while preventing anything external from entering.

For those unfamiliar with the helium issue, it is essential to understand why helium is used in deep-sea diving. Helium is one of the few gases that does not cause negative effects, such as nitrogen narcosis, which occurs when nitrogen is used at high pressures. As a result, helium replaces nitrogen in most deep-sea mixed gas diving applications.

In some cases, professional divers operate at great depths for extended periods while living in pressurized environments filled with an oxygen/helium gas mixture. When divers resurface and decompress after days or even weeks, the built-up gas must escape to prevent problems such as the crystal or crown being forced out, which can lead to serious injuries, including blindness.

That said, most divers do not spend extended periods in a pressurized environment, meaning they do not necessarily need a watch with a helium escape valve, regardless of their diving depth. However, with deep-diver watches like our 100ATM range, the valve is a critical feature, ensuring the watch is fit for purpose when needed.

Special Features of This Variant

This particular variant features a Sterile European NATO-pattern dial and is finished in black PVD stainless steel.

The matte black non-reflective PVD finish is often specified in military contracts for special forces and anti-terrorist units, as well as for various covert operations. Unlike lower-quality painted finishes that fade or wear off, PVD (Physical Vapor Deposition) alters the steel at a molecular level, ensuring it remains intact even under heavy use.

Although the PVD coating is highly durable, significant damage—such as deep gouges from metal impacts or prolonged abrasion against rough surfaces—can still wear it down.

While this watch is very similar to MWC's 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 requiring compensatory pressurization.
• The watch was also required to be resistant to magnetic fields up to 4,800 A/m (approximately 60 gauss).
• Additionally, the contract mandated a sterile dial, meaning the watch is unbranded.

The reasons for these requirements were not disclosed, but they represent unusually demanding specifications. As a result, this watch differs slightly from MWC’s other 100ATM models due to its high-altitude accuracy, magnetic resistance, and unbranded sterile dial.

Watch Features & Specifications

The movement is a high-quality Ronda 715Li quartz movement with a 10-year battery life and a hacking function for synchronization.

Dimensions & Specifications:

• Movement: Swiss Ronda 715Li quartz, hacking function, 10-year battery life
• Water Resistance: 100ATM / 3,280ft / 1,000m
• Crown: Screw-down
• Helium Escape Valve: Yes
• Width: 47mm (including crown) / 44mm (excluding crown)
• Bezel: Unidirectional, non-reflective with ceramic insert
• Thickness: 18mm
• Crystal Diameter: 31mm
• Crystal Type: Sapphire with anti-reflective coating
• Lug-to-Lug: 48mm
• Weight: 132g
• Case Material: 316L PVD stainless steel
• Illumination: Luminova on markers, hands, and bezel
• Strap: 24mm NATO webbing strap

Why Choose a Sapphire Crystal?

Many customers ask about the advantages of sapphire crystal over standard mineral crystal. Synthetic sapphire is the best material for watch crystals because it is:
✔ Extremely strong
✔ Shatter-resistant
✔ Highly scratch-resistant

These properties make sapphire crystal particularly appealing to:

• Military personnel
• Security forces
• Police officers
• Outdoor enthusiasts

These groups make up over 70% of our customer base.

To put this into perspective:

• Over 90% of cracked crystals reported by customers occur in watches with mineral glass.
• Even hardened mineral crystals do not match sapphire for durability under adverse conditions.

Why is Sapphire So Strong?

After sapphire glass is manufactured, it undergoes heat treatment to remove internal stresses, which can cause weaknesses. Once the watch crystal is formed, two layers of anti-reflective coating are applied for enhanced clarity.

Interestingly, sapphire crystal is now used in the latest iPhone models due to its superior strength. However, because sapphire is costly to produce, it is typically found only in high-end watches.

Final Thoughts

The MWC 100ATM Depthmaster is a high-performance dive watch designed for extreme environments. With its robust build, helium escape valve, ceramic bezel, sapphire crystal, and military-grade PVD finish, it meets the highest professional diving and military standards.