If you're going to use it in a car, I'd recommend getting a power inverter instead and just using your regular one. We got one for about $20 that works fine with my son's standard compressor.
We also just got an eFlow/Trio and can certainly vouch for it as a good choice if you can wrangle one out of the system.
We also just got an eFlow/Trio and can certainly vouch for it as a good choice if you can wrangle one out of the system.