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

DW644

This watch is a 100AT/24/SS/SL/22 below is a full description of this particular watch and the issues which it has (or is reported to have because in many cases the watches do not have significant issues, below that is the full information relating to this model from the factory website which gives full details of all of the dimensions, specification and other information relating to the watch.

We buy these watches from various defence auctions and other disposal sales and it's frequently the case that we find that there is actually nothing wrong with the watch but it has to be assumed it will have some form of fault though in most cases it's very minor or as described below. These watches are disposed of at low-cost because we find that one of the problems is pressure of time for our service staff in the UK and elsewhere and in most cases they have given them a quick check over and nothing is immediately apparent though we have to assume that there is either no real fault with the watch or something will reveal itself over time in which case it’s normally a simple case of a service, repair or battery exchange depending on the exact model

Model: 100AT/24/SS/SL/22

Condition: Excellent as can be seen in the images

Fault: Running Fine but the second hand needs resetting. This would be a routine job for any watchmaker.

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FACTORY DESCRIPTION

SKU: 100AT/24/SS/SL/22

The MWC "Depthmaster" range of Military Divers models are MWC's latest heavy-duty range and are both extremely robust with a sapphire crystal and suitable for diving with mixed gases at extreme depths due to the 100atm water resistance rating, they also have a wider strap at 24 mm (most military divers watches use a 20mm strap) and a non-scratch ceramic bezel which is easier to grip in very cold and icy conditions. This model also has tritium GTLS tubes for maximum nighttime and low light performance. The Depthmaster range is specifically designed for use by professional divers under challenging conditions.

All MWC 100ATM models are fitted with a helium escape valve, people often ask us how helium gets into a dive watch in the first place and the answer is very simple, essentially a helium molecule is among the smallest of all molecules. What this means is because they are so small even though the seals are working fine to keep water out the helium molecules can still get through and enter the watch even though other gases and water cannot.

The main users professionally of watches with helium escape valves are saturation divers who spend long periods of time at great depth with high pressure, the result is that the helium molecules can build up inside the watch creating pressure inside the case, this can inflict serious damage to the watch and even blow out the crystal or crown when it’s unscrewed, this is potentially extremely dangerous if for example you are just checking or resetting the time, it can also potentially write off the watch. What the helium escape valve does is automatically allow the helium molecules to escape from the watch during decompression when the watch returns to normal standard sea level pressure. The valve is only one way, so it lets the helium out but prevents anything external from getting in.

For anyone who does not know why helium is an issue, it’s important to understand why helium is employed for deep diving. The reason is that helium is one of the very few gasses which does not have negative effects such as we see with nitrogen which causes nitrogen narcosis, consequently helium is used to replace nitrogen in most deep-sea mixed gas diving applications.

In some situations, professional divers can operate at great depth for extended periods where they live in dry environments pressurised with an oxygen/helium mix. When the divers surface and decompress after days or even sometimes weeks this gas must be removed to prevent a problem as mentioned earlier such as the crystal or crown being blown out which can potentially injure or even blind someone.

The reality is that most divers will not be living in a pressurized environment for days or weeks on end, this means they will have no need for a watch equipped with a helium valve, regardless of how deep they dive but with deep diver watches such as our 100ATM range, it's essential the valve is there just in case it’s needed because the watch would not be fit for purpose without it.

The movement is a high-quality Swiss Ronda 715li with 10 Year Battery Life and a hacking function to enable synchronization. 

Dimensions and Specification: 

• Movement: Swiss Ronda 715li Quartz with 10-Year Battery Life
  
• Water Resistance: 100ATM / 3,280ft / 1000M
  
• Screw down crown
  
• Helium Escape Valve
  
• Width: Inc Crown 47 mm (Exc Crown 44 mm)
  
• Bezel Type: Unidirectional Non-Reflective with Ceramic Insert
  
• Thickness: 18 mm
  
• Crystal Diameter: 31 mm
  
• Crystal Type: Sapphire with Anti-Reflective Coating*
  
• Lug to Lug: 48 mm
  
• Weight: 140g
  
• Case: 316L Stainless Steel
  
• Illumination: GTLS Tritium on markers and hands Luminova on the bezel
  
• Strap: 24 mm NATO Webbing Strap