This thread got me thinking. Please bear with me. This morning I was airing up a car tire that was low. I used the gauge on airhose/trigger type assembly. I filled it to the appropriate level (51 lbs). Then I decided to use another gauge and it read 44 lbs. Whoa...7 lbs difference. I found another gauge I have used a lot and when I used it, it was around 44 lbs. Then it made me think, I have been using the hose assembly with the trigger for awhile now so when I thought I had the right amount of air in the tires, I was actually low. Granted, the two could be bad and the one with the high reading could be the good one, but I am doubting that. I will continue to check with a few other gauges I have (try to keep them in vehicles) to see what they record.