This product is mainly used for object acceleration and velocity measurement. Individual users can be used to measure the design speed of all kinds of playthings. Measuring speed range: 1-999m/s. Handheld type speed measuring instrument, with high accuracy measurement, 160 groups datas be recording. Mini size is easy to carry. Simple and easy operation. Metal and fully closed, this speed measuring instrument not affect by the sun and air current. High accuracy, with accurate measurement data. Humanized design unit conversion function., Weight: 0.37368353409 Pounds, Manufacturer: rirue