I had a problem with one of my tires going flat and was hoping it would be of some use if needed. The instructions are simple, I hooked it up to my bus but didn't get a PSI reading. Nothing is displayed on the LCD screen. However, I turned it on and the pump started to work. It didn't inflate my tire. Tried unplugging and plugging in multiple times, nothing. That does not work. So I wrote to the seller asking if I need to do something differently or if I should just send it back to have it replaced. No Answer. Nothing. And now the returns window has closed. The product can of course be defective, that happens. But if you refuse to communicate with your customers, you lose them for life, like in this case. Avoid this seller. They don't care if you have a problem with their products.