The US Divers Royal Master was only made for about two years (1964 to 1965) and is a must for any vintage scuba diver's display.  The Royal Master was replaced by the Royal Aquamaster.  This model was delivered to me with a short yoke and a beautiful label.  It is my understanding that all Royal Masters and the first Royal Aquamasters came with short yokes making the use of most banjo fittings impossible.