I love this device, it's portable, convenient and very easy to use. Just install it and forget about it until it reaches the limit you set. All four of my tires were a few pounds lighter. I set it at 34psi and after that it was around 34.5-35.5psi so around 0.5-1.5psi over my limit. It doesn't matter as I always check it with a pressure gauge to make sure it's reading correctly. It's much better to let off some air than to increase the set limit and turn the pump back on. It has enough lanyard to get to all your tires, but you may have to carry it through the driver's or passenger's door, depending on which side you need to fill. Overall, I recommend this device, but always check it with a pressure gauge. ***** After owning this device for several months, now it won't turn off when the set limit is reached, the numbers won't rise above the set limit on the display. However, using the pressure gauge in the tires, I found that it was well over the limit by 2psi (I had to turn it off manually). ***