complete garbage. Since the device has a screw connection and not a latch (like a gas station) you will lose about 5 psi just trying to unscrew the connection. The only way to get the tire to maintain the correct pressure (36psi for me) was to overinflate about 5psi and let the device run while I unscrewed the linkage. Specifically for the front tires that support the weight of the cylinder block. It took me 45 minutes + 5 YouTube videos + my entire swear dictionary to figure it out. Beware.