The DIR Zone PVD SPG Black - 300 Bars is the made out of high quality brass, and is most suitable for back gas and also stage/decompression cylinders. It is now coated with PVD (Physical Vapour Deposition) finish, that has a tougher resistance to scratches and corrosion. The diameter of this SPG is 52mm, and reads from 0-360 bars. This SPG can be used anywhere in the world even with 300 bar cylinders. The readings are spread out neatly so that the diver can have a clear view at any depth. It comes with a swivel spool with Viton O-Rings The readings and the needle on the dial is glow in the dark. Technical divers will like the feature of the burst disk at the back, in case of a failure, it does not blow to the face unlike plastic gauges.