This speed measurement instrument is mainly used for object acceleration and velocity measurement, individual users can be used to measure the design speed of all kinds of shoot playthings. High accuracy, with accurate measurement data, simple and easy operation. Large LCD display with backlit, you can see the data in the weak light environment clearly. Totally 2 versions available, you can choose according to your demands. Features: 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 shoot playthings. High accuracy, with accurate measurement data, simple and easy operation. Large LCD display with backlit, you can see the data in the weak light environment clearly. Support parameter setting function, you can set shutdown time, backlit on/off, adjust the unit and etc.. Operation interfaces switchable, you can switch and check different data according to your demands easily. Totally 2 versions available, please reading the difference between these 2 versions clearly before order: Common version: Standard configuration, built-in lithium battery. support record 30 groups of data, shutdown reset; default traditional Chinese, and support switch to English. Wifi version: with Wifi function; support record 120 groups of data, shutdown will not reset, support manual reset; default traditional Chinese, and support switch to English. Specifications: Name: Speed Measuring Instrument Material: aluminum Battery: 1 * 3.7V, 400mAh lithium battery (included) Version: common version, Wifi version (optional) Shoot speed: 0-3600s/min (0-60s/s) Initial velocity: 2-1500m/s (10-5000ft/s) Kinesthetic energies: 0-999J Shoot ranges: 0-999m Accuracy: error0.5% Host size: 44 * 73 * 33mm / 1.73 * 2.87 * 1.30in Package size: 130 * 80 * 90mm / 5.12 * 3.15 * 3.54in Package weight: 180g / 6.35ounce Packing List: 1 * Speed Measuring Instrument