I have used this item six times since purchasing it earlier this month and have a few opinions on it based on my usage. I've seen many portable air compressors under $100 and can tell you most of them are a waste of money. Today someone tried to inflate a low 40psi makeshift spare tire to 60psi and the device they ran for 10 minutes added the full 2 pounds of pressure. The tire only needed 1 pound more pressure. The job took about 5 minutes but it did the job. I've used other times to add up to 25 pounds of tire pressure without missing a beat. I inflated a patched tire from zero to 60psi on my Dodge D250 and it did, but turned off the heat sensor once the tire hit 60psi and it was HOT! As such, I would recommend starting the car when using this tire inflator, especially when attempting to inflate a tire that is near zero pressure. The tire pressure gauge on my unit isn't very accurate, but you should still use a regular gauge, not the one on the pump. Good device for the money but maybe I should upgrade to a $150 device if I was going to be using it regularly in my truck. Still a very worthwhile device for most people.