Vintage Double Hose

Charlie just brought me in a set of doubles that are marked US Navy Type A with a working pressure of 1800. They have adapters down to taper thread with a USD manifold on them. Hard to read but it looks like they have an original hydro of 2/49. They aren't in the best shape so he just wants to use them for display but my question is . . . does anyone have any history on this type of cylinder??

Those were either co2 life raft inflation cylinders or aircraft o2 cylinders converted to diving use. I had a set years ago. I still have one of them. The cylinders sometimes have SPUN stamped on them. The ones I had were stamped ICC3A 2015. The 1800psi cylinders were most likely for co2 service and the 2015 were for o2 service. They are plain carbon steel rather than 4130 chromium-molybdenum steel used for 3AA cylinders. The ones I had were made by Walter Kidde.

These are also Walter Kiddie. I also read . . I think in the PSI handbook . . . that they used to be wire wrapped in case they were damanged in battle??

I have heard about the wire wrapping but have never seen it. Mine also had "non-shat" stamped on them which I asume means non- shatterable which could be an indication they were wire wrapped.