Review on Millimeter Conversion Micrometer: High-precision Electronic Measuring Tool by Ricky Habbani

The main issue is that it's cheaply made so you may have to tape the battery cover on or if you slide the sensor the tiny battery will fall out. I think that's why they send an extra battery. The measurements were accurate after I calibrated it. You should also be aware that even if you turn it off, the sensor will automatically turn on and drain your battery if the sensor moves. It was annoying when you were out with him.