Product review (1 stars): Didn't Work
Upon opening the package, and activating the battery by pulling the plastic shipping tab, the unit did not work. I found that gently shaking the unit would give me intermittent readings. I removed the battery compartment cover, and found that the electric leads would only make contact with the battery if the battery was held precisely in place (against a small spring). The battery cover did not hold the battery precisely in the required position - hence the intermittent operation. I can't explain why some people have no problem with this unit and it works fine for them, as this seems to me to be a flawed design issue. All I can say is that mine was unusable and I returned it.