Was going through old threads, and this question never got answered. It so happens I have one of these devices. There seems to be some confusion between the Pneolator and the Portalator here. While both MSA products, the Portalator was newer. Mine dates from 1964, the Pneolators are more 1950s. The Portalator is an oxygen-powered, pressure cycled "demand valve" like was typical. A Google search will turn up newspaper stories where Fire Departments and so forth were getting them up to at least 1970. The advertisement below shows one difference between the Pneolator and Portalator - dual patient capability with two demand valve option. Venturi aspirator too. Like most units, no "free flow" oxygen for a nasal cannula/simplemask /non-rebreather mask we all but exclusively use today. Infant and adult masks. There's also a transfilling valve to refill the cylinder from a bigger tank without removing it from the regulator, there's an extension hose mountedin the bottom left of the photo that does this. The green nylon thing you see is the carry strap. Unfortunately, my test lung was crumpled and dry rotted when it arrived.
Here's mine that I picked up fairly recently. It's in the original case, but no second demand valve. There's a property tag on it from an industrial setting where it came from. I collected old prehospital care and civil defense "junk" before the idea of getting the ambulances themselves crossed my mind. I have a lot of old resuscitators in particular, so if any questions or need for photos - let me know and I will try.