This digital tire pressure gauge is well made and feels like a quality product in my hand. It has separate on/off and units buttons, which are handier compared to one button for both functions in some other products. The permanent battery indicator is great to have to avoid dead battery when using it at the track. I have no means to verify its accuracy of +/-0.5%. Also it does not come with a certification validating the accuracy. Another good design is that the gauge reads tire pressure without the need to reset to zero like most other products. I gave it 4 stars because in other reviews, some gauges were found to be leaking when they arrived. This reflects the the quality control is not professional.