: thats expensive, got a regulator in an hardware store for an homemade
: compressor (fridge motor, to use with airbrush) for the equvalent of 15$,
: the fixed ones were even less and smaller.

No question the price is (currently) a bit steep. I doubt it is patented -- too many preexisting ideas going back far too many years -- so expect some other companies to come out with their own versions at more competitive prices.

Small compressors can do a very nice job. Couple them with a storage tank and you can get the pressure up to where you need it, and build up enough reserve to keep you working at a steady pace. The problem this company is trying to address is working without wires or supplemental power.

40 years ago U.S. Divers sold a hose that attached to a SCUBA regulator and allowed you to fill your inflatable raft, or car tires, with compressed air from a SCUBA tank. I made something tht went one better. I added a controllable regulator to mine, so I could dial in the output pressure.

I have a common two-stage SCUBA regulator. The first stage is clamped onto the compressed air tank and reduces the pressure from about 2200 psi down to about 100 psi over the ambient pressure. (the exact output would vary with how deep you were. above water I got about 105 psi out. I discovered that the connections on my regulator were 3/8th inch fine thread, with an "o" ring seal. So, with a short turn on a lathe I rethreaded one end of a short section of (nominal) 1/8th inch water pipe to fit that regulator port.

An off-the-shelf adapter allowed me to screw the standard threaded end of that converted pipe nipple into a standard 1/4 inch NPT hole on a standard air regulator (about $19 at the time from Sears). I unscrewed the second stage of my regulator (the mouthpiece and hose) and threaded my Sears regulator onto the 1st stage of my SCUBA regulator, and had a very controllable tank of compressed air for airbrushing photos (one of my sidelines at the time) as well as filling up tires on the car and bicycle. I found the whole set up cheaper than either an airbrush compressor (with tank and regulator) or a CO2 tank and regulator at the time --and I got to write off the SCUBA tank as a business expense.

What I'd like to do is find a way to safely reuse those empty, disposable, propane tanks. They should hold enough air at 300 psi to partially fill a liferaft, but I'm not about to experiment with something that could easily explode in my face. On the other hand, they do make cylinders of pure oxygen which are the same size, and only about $8 each. I wonder how many cubic feet are in each one.

Just some thoughts.

PGJ