Vari Power Meter measures the exact current engine speed and also records its actual running time in units of minutes, allowing for precise planning of service tasks and showing the actually worked motor hours of the machine or engine. VARI Power Meter is recommended for all single-cylinder 2-stroke and 4-stroke combustion engines and is also suitable for all lawn mowers, mulchers, small tractors, garden tractors, brush cutters, snow blowers, tillers, power generators, small boat engines, garden vacuums, asphalt cutters, and other motorized machines.