I received my new Weber jet gauge today and I tested a 190 air corrector with the 1.90 mm gauge. It was spot on. I then measured the gauge with a HF digital caliper and it read 1.85 mm, so I tested with another HF digital caliper and it read 1.86 mm. I then measured it with a Starrett micrometer and it was .075" which is 1.90 mm. I then measured the gauge with an old HF analog caliper and it agreed with the Starrett micrometer. So the bottom line is don't trust HF digital calipers for critical measurements.