1. The battery is a 300mAH standard special battery, the voltage is 3.7V and the is 14250 2. The charging and discharging interface is -USB; the voltage is DC5V 3. The benchmark is not in . Fully charge in sequence two months. The board has -in charge management and charge and discharge protection. Note the battery polarity must not be reversed. 4. The output interface is a 2mm banana socket, and there is an output interface for calibration. HP3458A eight-and-a-half digits multimeter to calibrate ( after full preheating). Re-calibration calibration conditions, time and calibration value record card will be pasted on the benchmark, please keep it properly 5. Press and hold for 2 seconds to turn on the machine. When turning on, the four indicator lights will light up at the time, and then output the 2.5V reference voltage. After turning on, short press the button to switch the gears, followed by 2.5V-5V-7.5V-10V and long press for three seconds To shut , the voltage indicator will go out immediately after shutting Material:plastic colour:yellow Package Contents: 1 * Reference Module Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.