I'm not certain if some people received products from a different manufacturer or lot, but my product is excellent. It is very sturdy, strong construction and has tested as being accurate in it's measuring ability. My original battery arrived working as well. I've had no issues with it at all. For the price, this thing was a steal. I love having the nice case as well.*note-it only comes with instructions and an extra battery, not a certificate like another post listed.