Pressure breathing O2 regulator these days?

Back in the old days (you know, like the 1980s?), the standard pressure breathing O2 regulator for wave flying was the A14. They were (relatively) cheap and common, and pretty much all of the players like Bikle and Harris used them.

Does anybody have a sense of what is being used these days? I looked around a couple of years ago, and it seemed like A14s were no longer common, and getting one overhauled was rather an expensive proposition. And of course, by now all of the rubber parts would be half a century old, so the one in the back of the closet is probably junk. And when you are trusting a mechanical device to jam a calibrated pressure of O2 into your alveoli, you want it done right.

So, what is currently being used for pressure breathing, and where do folks get them?

Thanks, Bob K.