Based on the previous good reviews, it sounds like I got a lemon. My set of calipers sometimes loses its mind. The digital readout will start incrementing even without sliding the caliper jaws. If I leave the calipers on my bench, I sometimes come back and find that the readout has climbed to a ridiculously high number like 90" (the calipers are obviously only 12" long).If I pull the calipers out quickly it will lose count along the way. Full travel of the calipers should be 12.065", but if I pull them open rapidly it only counts to 11" or so.For me, these were a waste of $40. I tried to cheap out since my work isn't typically critical to more than .010", but these are horrible. I bought a $125 economy set out of McMaster instead and they work great.