I've only used it once to inflate all the tires on my car and my wife's SUV and the gauge reading is 2psi lower than what's actually in the tires. I'm not sure if it gets more accurate or not after a few uses, but at least it's consistent, meaning I can pump the air 2 degrees deeper than the meter says. The sealing air liner also lets air through, but stops when you hold the tube straight onto the tire's valve stem. The construction looks pretty solid. The trigger is easy to use, and resettingβ¦