Vintage Double Hose

A customer brought about 15 boxes worth of dive gear ranging a 40 year diving career that his father had. In one of the boxes was this piece. I got incredibly excited since it looks like it can be a part of a triple manifold but no searches online have helped so far. I know I shouldn't get my hopes up that I can use this for a triple set but now I'm just curious on what it is. Any help is appreciated.

As an aside there was lots of cool gear. Including some Piel micro regs and some Apeks regs from the 80s. along with some nice single hoses from seamless in good condition.

What do the ends look like? Are there threads for a plug or j-valve? Is it smooth for insertion of an o-ring'd manifold?

The ends are female and fit standard manifold plugs. Blue steel type thread.

Cool! (for S&G, I'd try putting an H-Valve on each side, and put it on a big tank....)