Review on Fowler 54 554 611 Electronic 0 200 0 590 Resolution by Bud Crabtree

This is a good quality internal caliper. It lasts a while, the only thing subject to wear and tear are the "teeth" at the end of the arrow. If they wear out a lot over time, you can't recalibrate them. The original lasted a long time though, so I bought two more and calibrated both with one as a backup for the other.