Specification: Operating voltage: DC4.2V Accuracy: Test error less than or equal to 0.5% Measuring range: 1-999m/s Battery (built-in): 450mAh Operating ambient temperature: -10°C - 60°C Speed measurement range: 1-999m/s Energy measurement range: 1-800J Weight input range 0.1-10g Speed record: 40 groups Item size: 130 * 80 * 50mm / 5.1 * 3.1 * 2.0in Features: The panel mainly consists of digital display tube, function, key and LED indicator. The function keys are miniature touch buttons. Effectively mitigate the effect of test time. Improved stability and accuracy. Display buttons make and view test data are very convenient. Mini size is easy to carry. Simple and easy to operate. Highly accurate measurement. Due to the high precision of the device, the same as the card rail, and fixed equipment each time after the same action, and can be made with the guide rail with the use of models in parallel, so the measurement results of the error is small, dynamic fluctuations are small. The function is more abundant. Not only can measure the speed, but also can measure the motion energy, at the same time can record up to 40 groups of speed and 40 groups of motion energy value. Multiple power management and protection. Over-charging, over-discharging and short-circuit protection, integrated smart shutdown and low-power shutdown. Product List 1*Speed measuring tool Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.