Save your bucks.
I use a sheet of 400 grit Emery paper rolled into a tube about 1.5" in diameter and held in place with rubber bands on each end. Hold the knife in one hand (with your hand braced on your knee while sitting in a chair is best). Hold one end of the Emery tube in the other hand. While keeping the knife still, place the end of the Emery tube against the knife edge and move it rapidly side-to-side from the knife tip to the handle with wrist action of the hand holding the tube. Keep the angle the same throughout the operation. Do that to both sides of the knife edge and you will get a scary sharp knife.
(Sharpen all of your kitchen knives like this and you wife will put on that black negligee.)
