Seems to work OK, but doesn't look like the picture. The car valve cap on the side suggests that you can connect a pump to the side and pump up the ball through the gauge. So when you get to the right pressure you can stop. The one I got has a push valve on the side so its just for measuring the pressure and lowering it if it's too high. Other cheaper gauges are like that. I was expecting a gauge that I could use to get the correct P while inflating.