Both the Big Indian and the Mark 11 are the same case, movement, dial, but the markings are different. The Mark 11 I believe was for the RAF Vulcan bomber like it was used in the James Bond movie. It is the large delta wing nuclear bomber. Not to be confused with the IWC or JLC Mark 11. The Longines Mark 11 has a real history, the Big Indian no one really knows what they are for correct?