Usually mowing is distinguished from reaping, which uses similar implements, but is the traditional term for harvesting grain crops, e.g. with reapers and combines.
There are also dedicated self-propelled cutting machines, which often have the mower units mounted at the front and sides for easy visibility by the driver.
The grass, or other plant matter, is cut between the sharp edges of the sickle sections and the finger-plates (this action can be likened to an electric hair clipper).
The bar rides on the ground, supported on a skid at the inner end, and it can be tilted to adjust the height of the cut.
When these mowers are tractor-mounted they are easily capable of mowing grass at up to 10 miles per hour (16 km/h) in optimal conditions.
Some models are designed to be mounted in double and triple sets on a tractor, one in the front and one at each side, thus able to cut up to 20 foot (6 metre) swaths.
This type of mower is used to produce consistently short and even grass on bowling greens, lawns, parks and sports grounds.
These types are used on rough ground, where the blades may frequently be fouled by other objects, or on tougher vegetation than grass, such as brush (scrub).
Drum mowers are particularly effective in tall and dense grass, where their powerful cutting action can make quick work of the task.