Did you know Power Tank digital gauges can be recalibrate if you suspect it is inaccurate? It's a simple process and will take less than 5 minutes if you have a tire pressure gauge handy. The recalibration will then only be as accurate as your other gauge, so use a quality gauge that you trust. Or you can send your gauge in to us, and we will run the calibration on our calibrated Racer Series test gauge. This is one of the benefits of upgrading to a digital tire inflator from our analog models. You also get twice the accuracy and a back light.