The Pelagos FXD model, where FXD refers to the extra robust fixed strap bars of the case, was developed in conjunction with the French Navy's combat swimmers. Waterproof to 200m (660 ft), it was designed for underwater navigation and is optimized for professional use. Also in the range is a model that pays tribute to the decades of TUDOR watches on the wrists of US Navy divers. Complete with fixed strap bars, a titanium case, a high-performance Manufacture Calibre and a unidirectional elapsed-time rotating bezel, it comes as the ultimate modern “Milsub” (short for Military Submariner) of yesteryear. Visually in line with a late ‘60s-era TUDOR Oyster Prince Submariner; it incorporates elements from the US military specifications for diving watches. In short, the FXD range is the product of TUDOR’s cooperation with two military organizations.