The IM200 Professional Sharpening System is great for producing and maintaining really sharp edges on all your cutlery. This device is a household version of Norton's famous IM313 sharpener which has been the sharpening standard for professional chefs for over 80 years. Its coarse stone is fast cutting for repairing damaged and severely dull edges. The medium stone sharpens dull edges quickly and upgrades the finish left by the coarse stone. The fine stone provides an excellent edsge for most food preparation requirements and should be used to maintain your edge on a regular basis.