This was one of the cheapest dial indicators but it was accurate from the start. It matched the digital pressure gauge I have and after my car dealer performed a scheduled maintenance including tire pressure check, this gauge showed the tires were within the factory recommended PSI. So I am assuming their caliber and this one is correct. It seems unlikely that 3 bugs are on the same bug. It's easy to seal it against the tire valve so you can read it without constantly leaking air. Also, there is a valve that holds the pressure so you can take it off the valve and get the reading. Then simply press the small button on the stem to reset the dial to zero. The only thing I want to change is the point angle. While the tip rotation allows the valve stem to be reached from almost any angle, I would have liked a more direct connection. It doesn't matter as it just makes me handle the pressure a little quicker. My old dial gauge had a direct connection and I never had a reading problem no matter where the bar ended.