Drum mowers are a type of mower usually used as part of the harvesting of forage (grass) crops for hay or silage in either bales or a silage clamp. The crop is mowed and left to wilt before being baled as hay or silage or being collected by a silage harvester and transported to the storage pit. Drum mowers can be mounted on the tractors 3-point linkage or trailed. Modern high output units comprise several sections that fold/lift for transport but can cut a swath of metres (ft) wide or more in one pass.