Easy to use on a countertop by simply sliding the knife blade through the slots, this 3-stage system features 3 distinct functions. Slot 1 is a ceramic rod that fine-tunes for a clean, polished edge. Slot 2 is a carbide sharpening rod that sharpens damaged serrated blades, with guides to help ensure the perfect angle as you slide the blade through the slot. Lastly, Slot 3 is a carbide sharpening rod that repairs and straightens damaged blades. The comfortable handle and the nonslip base provide stability and keep the sharpener from slipping on surfaces while using. The compact size allows for easy storage. Made of stainless steel and plastic.