A cutting board is a durable board on which to place material for cutting. The kitchen cutting board is commonly used in preparing food; other types exist for cutting raw materials such as leather or plastic. Kitchen cutting boards are often made of wood or plastic and come in various widths and sizes. There are also cutting boards made of glass, steel, or marble, which are easier to clean than wooden or plastic ones such as nylon or corian, but tend to damage knives due to their hardness. Rough cutting edges—such as serrated knives—abrade and damage a cutting surface more rapidly than do smooth cutting implements.