Bob Kramer is widely recognized for his extremely sharp high performing carbon steel knives. To keep these knives maintained and sharp, Bob Kramer by Zwilling has introduced an entire collection of water stones and stropping block. Stropping Blocks have been used for centuries by barbershops to maintain and sharpen their edge on their razors. You can use a stropping block between sharpening. A stropping block will place a polished and shiny edge on your knife blade.