RS Mechanical Tachometers Our mechanical contact tachometers feature an easy to read and large dial as well as having a range of contact adapters to make them both easy and convenient to use. Due to their design they can be used in areas where electronics are not suitable. They can be used with one hand operation and are encased in rubber to give excellent protection and grip feel. Metric and Imperial options No batteries required Over-sized 3" Dial (70 mm) uses 2 separate color scales making reading RPM and Surface Speed quick and easy Accuracy of ± 0.5% Full Scale 3-Position Range Selector Switch provides highest possible resolution for each application Memory button holds pointer in "last" position until reset