I bought one of those 12V plug in units from NAPA, it sucked more than it blew. I tried to blow up an air mattress and an hour later it was only half full so I gave up. It went into the garbage. I recently purchased another "heavy duty" one to replace it. First time using it I was filling a trailer tire, it got up to 35psi then it quit, motor burned up. The tag on the cord said only use it for 10 minutes then let it cool for ten minutes, I doubt I had it hooked up for more than 11 minutes. What a POS
