Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Didn't seem to work at all.....

I've never used a unit like this before, but either there was a problem with my technique or the unit was simply defective. Following unclear directions as best I could I felt no current and noticed no results. I will add that the tip was so delicate that I may have wrecked it before I ever got started.This may be a good device if you know what you are doing (and are super careful) but I was not able to get any use out of it despite repeated patient attempts....