Nibblers are used for cutting sheet metal with minimal distortion. There are two distinct types of nibblers. One type operates much like a punch and die, with a blade that moves in a linear fashion against a fixed die, removing small bits of metal and leaving a kerf. Another type operates similar to tin snips, but shears the sheet along two parallel tracks, rolling up the waste in a tight spiral as it cuts. Nibblers may be manual or electrically and sometimes pneumatically powered.