Testo 470 optical and mechanical tachometer Simple operation. Optical and mechanical measurement of rotation speed. Rotation speed, speed and length measurement. Memorisation of min. and max. values, as well as the last value at power down. Automatic stop. Delivered in a transit case with adaptor, funnel, wheel, reflective strips, batteries and instructions for use. Set of 5 reflective strips available separately. Available in calibrated version. 光学非激光接触