It is equipped with a helium valve, to allow saturation diving. It is also resistant to magnetic fields and scratching: indeed, U53 is made entirely of grade 5 titanium, a light, comfortable metal which is very well tolerated by the skin even in high moisture conditions yet is hard enough to withstand most scratches. U53 also stands out among classic types of diver by showcasing its movement in spectacular fashion. The Angelus A-300 is a skeleton calibre characterised by its large bridges. By their openwork in the centre, which specifically evokes the design of Angelus’ calibres.