1. The battery is a 300mAH standard special battery, the voltage is 3.7V and the model is 14250 2. The charging and discharging interface is micro-USB; the voltage is DC5V 3. The benchmark is not in use. Fully charge in sequence every two months. The board has built-in charge management and charge and discharge protection. Note that the battery polarity must not be reversed. 4. The output interface is a 2mm banana socket, and there is an SMA output interface for calibration. Use HP3458A eight-and-a-half digits multimeter to calibrate (use 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 same 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 down, the voltage indicator will go out immediately after shutting down Material:plastic colour:yellow Package Contents: 1 * Reference Module Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.