This tachometer features both the ability to measure RPM (revolutions per minute) in rotational equipment and surface speed m/min (meter per minute) / ft/min (feet per minute) with included contact adapters. The R7140 uses visible light for non-contact measurements to read up to 12″ (300mm) from any target. The R7140 features a durable ABS plastic housing to assure years of maintenance free performance.