The 42mm case, water resistant to 600m, is a pretty good start. Most divers go no deeper than 39m so 600m water resistance leaves a significant margin to play with. The case is cut from marine grade (the wet stuff rather than the green beret type) stainless steel and weighs in at just 103g. It’s grey DLC coated (a matching bracelet to fit the 22mm lugs is due later in September) and the caseback screws down and features a laser engraving of the Royal Marines’ crest.
The two crowns respectively wind and set the movement and rotate the inner compass bezel. The latter, like the dial plots, hands, and ceramic bezel are all coated with Grade X1 GL C1 Super-LumiNova so, when you’re on exercise, up to your chin in mud, in a ditch in the middle of the night you’ll at least know where you are and how long until you can be somewhere else. The dial is a light carbon fibre/resin composite.