Graters come in several shapes the most popular styles are flat, cylindrical and box-shape. They're used to reduce hard foods to small particles or long, thin strips. Most graters are made of metal or plastic that has been perforated with sharp-edged, small- or medium-size holes or slits. Many have handles at the top for a sure grip. Graters made of stainless steel will not rust, whereas those of tinned steel will.