The Duke is a full-face mask (FFM) and it is designed to give the user the opportunity to breathe easily. Obviously, it’s not the first of its type. In fact, we could say that Cressi’s Medusa mask was the first FFM but it didn’t separate the breathing chamber from the vision chamber.Cressi owned a patent for the Medusa mask.Our new system of breathing, that we have designed are patenting, because it doesn’t use the old system of breathing through a central tube system, so it doesn’t require the need for forced breath to travel a longer distance and open more than one valve.What else makes our mask different from all the others? And how does the Duke allow the diver to breathe freely and also expel CO2 build-up and not fog up the vision chamber?