_x000D_ _x000D_ _x000D_ 1. The board is equipped with built-in charging management and charging and discharging protection _x000D_ 2. The calibration value is a six and a half digit count, accurate and reliable. According to usage requirements, it is recommended to recalibrate the calibration conditions every two years. The time and calibration value record card will be pasted on the benchmark _x000D_ 3. With indicator lights, press and hold for 2 seconds before turning on. When turning on, all four indicator lights light up simultaneously _x000D_ 4. This product is a precision voltage reference that can be programmed with four common output voltages: 10.0 V, 7.50 V, 5.00 V, and 2.50 V _x000D_ 5. Voltage output interface with 2mm copper test socket for easy insertion into a pen type multimeter for measuring or calibrating other instruments. Charging and discharging interface:micro-USB. Output interface:2mm banana socket _x000D_ _x000D_ Battery:300mAH benchmark dedicated battery (product does not include batteries) _x000D_ Battery voltage:3.7V _x000D_ Battery model:14250 _x000D_ Voltage:DC 5V _x000D_ Instructions: _x000D_ 1. The benchmark is not used to fully charge the battery every two months. The board is equipped with built-in charging management and charging and discharging protection. Please note that the battery polarity should not be reversed _x000D_ 2. The output interface is a 2mm banana socket, and there is also an SMA output interface calibration. The HP3458A eight and a half digit multimeter is used for calibration (after sufficient preheating), and the calibration value is six and a half digits for counting, which is accurate and reliable. According to usage requirements, it is recommended to recalibrate the calibration conditions every two years. The time and calibration value record card will be pasted on the benchmark, please keep it properly _x000D_ 3. Press and hold for 2 seconds before turning on the machine.When turning on, all four indicator lights will light up at the same time, and then output a 2.5V reference voltage. After turning on the machine, briefly press the button to switch gears, in order of 2.5V-5V-7.5V-10V. Press and hold for 3 seconds to turn off the machine. After turning off the machine, the voltage indicator light will immediately turn off _x000D_ Colour:Yellow _x000D_ Material:PC+Metal _x000D_ _x000D_ Package Contents: _x000D_ 1 x voltage reference board _x000D_ _x000D_ Only the above package content, other products are not included. _x000D_ Note: Light reflection 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. _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_