Rotation speed control counters are used to measure revolutions per minute, as well as the speed of rotating objects, according to an optical measuring principle. This provides maximum safety during the inspection or installation of machines, turbines, pumps or motors. Depending on the version, calculations of other values such as length or distance is possible. This is particularly beneficial for goods recorded by winding machines. Compact, robust and battery powered – they can be used in any kind of environment. Rotation speed control counters also play a useful role in model construction. They are used for testing small engines, propellers or crankshafts, for example.