Air-powered shears and nibblers make straight or curved cuts in sheet metal. They run on compressed air and contain few moving parts, so they typically run cool, have a long lifespan, and weigh less than corded or cordless models. Shears move their pivoting blade against their fixed blade to cut like scissors through flat sheets. They cut more slowly than nibblers but leave smoother edges and less mess. Nibblers punch a series of small holes to cut flat, corrugated, or uneven sheet metal. They start cuts at the edge or in the center of material. Also known as nibbling cutters, they leave shavings and rough edges but cut tighter curves and more precise corners than shears.