This set is from the late 50's or early 60's and is best suited for a vintage scuba gear collector. This setup is designed to use a horse collar BC you put on first.
The tanks are too small to be provide enough gas for a serious doubles set - most current steel single tanks have a larger capacity.
The tanks are not designed to handle even current low pressure - looks like the pressure limit is 2015psi.
The manifold is outdated. The J valve on the one tank was designed for the era when a pressure gauge was not used - a diver started the dive with the J valve in the UP position and when breathing became difficult, he pulled the J valve to the DOWN position and that release the remaining 300-500psi to be used on the diver's ascent. Forget about planning a deco dive!
Interesting comparison is that the current Navy SEALS use a similar setup - the diver can scooter underwater from a Zodiak boat and then ditch the tanks near shore and keep the horse collar BC on for flotation, whereas with the current Hogarthian setup with a harness, backplate and wing, the whole rig is bolted together and doesn't offer the same flexibility.
