The Superflow MV-50 seems very hit or miss. I ordered one off of Amazon several months back when they had it as "Deal of The Day". Took it to Utah on a trip and it filled 4 32X11.50 tires from 18psi to 35psi rather nicely. 2 days later it filled 2 of the same tires, started skipping and shut off. It restarted to fill the 3rd to 30 psi and shut off again to never restart! It wasn't super hot and I used it according to directions. It was outside of Amazon's
window for returns so now I must send it back to the manufacturer (haven't done so yet).
There is a thread somewhere out there where a gentlemen upgraded the wiring, fuse, and air hose. I meant to do this before I left but ran out of time. If you get one definitely check that out.
Just be advised that the mv-50 may work wonderfully for you for years (like quite a many vouch for) or it may fill 6 and a half tires, die, and leave you driving forty miles back to Moab on an front tire with 18 psi in it.