PfcAJ
Contributor
I am not aware of a doubles manifold that can be separated under pressure that has been made for decades, like before a lot of divers on this board were born. I don't think any of them work on 215mm/8½" standard bands today.
The Lola manifold can be separated.
Golem Gear, Inc. - LOLA Universal DIN Valve
But they're quite uncommon at present. I think its a cool design though.
OP, this is probably NOT what you have. So you can't separate under pressure. Sorry m8.