The button has to be continuously held down and the plastic feels a little cheap but its a Ryobi so I think its good for the price. It came with a battery and charger which is nice. No need to plug into the car. The battery actually charged quickly as well although I'm not saying its a "quick charger." Just seemed to work quickly for me. After letting go of the trigger/button the psi sets a couple pounds lower then compared to when holding the trigger down. Using the PSI after releasing the trigger, it was only .5psi off from the reading on my digital Slime gauge. That's pretty good to me. I would recommend for quick adjustments as a car owner but not if you're actually going to be working routinely on tires.