Our model 401 is NSF Certified and has a pop-out, easy to clean and replaceable knife guidance system. Electric knife sharpener has a precision guidance system to maintain perfect edge, ABS plastic knife guide for easier cleaning and ease of operation. Knife guide allows knife heel to be inserted closer to stone to maximize sharpening area. Sharpens knives from 3⁄16 of an inch to cleaver blades. Grinding wheel assembly is replaceable.