Bought this to maintain my knives and perhaps a few friends. Took about 25 minutes on each of kitchen knives and now they are consistantly sharp and will just take a few minutes every week to maintain the edge. I gave this 4 stars instead of 5 because the clamp does not hold my 12 inch chef knife as well as it could. I clamped the unit to a wooden table and sat as I went through the different grits. Unfortunately, the knife began to tilt and even though I retightened the clamp and used the included pads, the knife still moved slightly. I think I will try a thin rubber gasket between the clamp and blade next to see if that helps. I'm still satisfied with the edge and hope they will develop something to hold the blade even better. Perhaps 5 stars sometime later.......Bob
