The first problem I found was that the quick release connector (called the plug) on the unit did not mate with the industry standard interchangeable pneumatic chuck that is used in every store in the UNITED STATES. The fit is too short. I replaced it with a standard fitting and it worked but not very accurate, at least a few psi. And be careful when changing the fitting. The body of the device is not made of steel but of die-cast zinc and is not very durable. Be careful when clamping it in a vise to replace the fitting.