Well.....It may be time to start talking about something that some find a lower cost option to a typical demand valve.
I can't take credit for the initial find. I was asked by someone to evaluate an Amazon buy to see if it could be adapted to our uses.
Before I go on.....the following should be considered solely as information and not a recommendation for use by me or anyone else for that matter. In other words, if you try this and it doesn't work as intended, it's not my fault because I'm not telling you that you should do any of this.
First....on Amazon we have this item. If you look closely, the provided hose is for scuba gear.....that's because that's what this device is sold as. BUT....if you happen to be surfing the web and end up here you will find a hose geared more towards our uses. If you find that one too short this one might be more your style. Now if you have a regulator such as this commonly found unit, your redneck, off label, completely unauthorized and not recommended by anyone demand valve setup is complete. Swap out the original hose for one geared towards our use and you're ready to roll. As with any O2 equipment, ALWAYS check for leaks and discontinue use until the leak is fixed. Never use pipe tape on O2 fittings. Never. Just don't do it.
As with any set up....always turn the tank off when not in use.
I've used it briefly and a fine fellow in the northeast have been testing one I sent him for a few months with no complaints.