This is a used power inverter. I've had it for a couple of years, bought it new, and used it two times. It has been sitting in the back of my shelf since.
I pulled it out and tested it with a 12 volt battery. It is in fine working condition..I tested it with a low voltage condition and it did what it was supposed to do. It sent a warning of low voltage and shut off.
I then tested it with a furnace motor and it did the required shut down. If the inverter senses a power surge requirement to get a motor running, it will shut down to not harm itself.
It's limit test were both pass.
I declare that this used inverter is in good working condition dition and there is no reason why you wouldn't get years of performance out of it.
Oh yeah, it has a USB port.