NO BATTERY needed. Will still work with battery if you have one. The sale of this item may be subject to strict regulation by the U.S. Food and Drug Administration and state and local regulatory agencies.
I purchased this because the picture showed a model that is lit up and appears to function. It obviously had a power supply. So I made the assumption that there would be a power supply for it. I purchased it and I don’t know if it works or not because there’s no way to turn it on. If they had not had a picture of it looking like it worked, I would not have considered buying it. It’s worthless to me.
Performs as expected. A lot of variation in the readings probably relates to the quality of the device (vs, more professional products) but it seems to give a average range that is useful. The cable, probe, base, batteries worked as advertised.