The 320 electric knife sharpener from Chef's Choice is a professional 2-stage sharpener that sharpens both straight edge and serrated knives to better than factory edges. This black sharpener is for 20 degree edges and features 2 stages with precision angle control. The 1st stage features 100% diamond abrasives while the the 2nd stage features unique stropping and polishing disks for unbelievable sharpness.