IWC W.W.W. Military Watch Mark X 10 caliber 83 vintage vtg watch

This is the legendary and rare IWC W.W.W. World War II Mark X watch ! 

1940's 

IWC caliber 83 movement 

15 jewels 

Manual winding 

Fully serviced in May, 2014 

Black dial with Arabic numerals and luminous dots 

Subsidiary seconds at 6, white IWC and broad arrow 

Stainless steel case with snap on stainless steel back stamped with broad arrow and W.W.W M16001 

W.W.W (Watch, Wrist, Waterproof) 

Case, dial and movement IWC signed, all original 

35 mm and 11 mm thin 

Do you prefer the nylon NATO strap or the original leather open end strap?