It works OK, it calculates the bodyfat a little bit higher than I was expected but since I am using only that tool I can see that my bodyfat decreases with the time(I have been doing intensive cardio the last three months). I believe the micro chip that is inside calculates wrong it shows me fat :-)) (the forth setting) and I am skinny guy, ectomorph with tiny bones and hard gainer. That is OK, as long as the percentage is decreasing. It has that error probably because I gained 10 pounds the last year and a half (weight lifting) but I still look skinny. p.s. If you measure with wet hands it will show you less percentage of bodyfat. I would recommend it as an inexpensive tool to check for any fluctuations in the amount of the bodyfat.