I had my daughter shave my head and love it. This tool was a game changer for me. Using a normal razer was horrible. I will say that I need to put my index finger above the razor to get a clean consistent shave and to add a little pressure. I am not engineer but the shave is way better when I add a light pressure, and only wish the S4 had something between my finger and the razor. 6 blades is a must and not sure why anyone wouldn't use those.