The first measurement I took went smoothly except that I noticed the needle slowly going down when I stood up after the measurement. Of course, as per other reviews, I had an air leak from the pressure release button. I've tried finger tightening various bolts but to no avail. Subsequent readings have shown me how difficult it is to get a good seal with this on a car tire valve stem - the alignment has to be EXACT! I have never experienced such a tricky tire pressure gauge in my life. On the way back from the UPS store to return this gem, I stopped at one of the top auto parts chains in the country and bought a cheap Bourdon tube pressure gauge for 1/3 the cost of the battery. Miraculously, the cheap one worked stably. Yes, cheap looks and feels cheap and probably won't last long, but at least it worked! Regardless of the quality of this sensor, Amazon's shipping service delayed this package for days and their website/chat will not let me get a refund or better status. A real downgrade of Amazon's "service". Again, please use UPS instead of USPS for shipping - they know what they are doing!