I am a locksmith by trade and work to +/- 0.005 inch on most sizes. I have decided to purchase a replacement set of calipers for larger parts. These calipers have proven to be more accurate and easier to use than I expected. They turn on automatically when you start moving them and they always remember their position and that's really my only complaint that they're a bit rough but the more I use them the better it gets. thousandth. The other wing of our company is managed by an engineer from Europe, so all sizes are in metric. These calipers are nice, just push a button and start getting into millimeters. bad. Overall, I'm happier with these calipers than I expected. And if someone hits my toolbox with a rag and throws these babies on the floor, no tears will be shed and I'll just buy another set. I think there's a certain virtue in that. I recommend these calendars especially for the money