I had a finger chopper over 50 years ago and it was a high quality device. Made of metal (unlike the transparent ones I bought for my grandchildren from you folks) so no one saw how the blades were rotated. Of course back then we (budding magicians) were expected to practice and use common sense so the there was a very sharp blade on one side. You could chop two carrots cleanly for openers then set the chopper and place your finger in the upper hole and a carrot in the bottom hole. SLAM your finger (or volunteer's from audience) remained complete without a mark while the carrot, string bean or even cigarette was cleanly cut. Very impressive and as a teenager it was a great trick to own. Very disappointed with the ones I bought/