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 be pasted on the benchmark 1. The board is equipped with built-in charging management and charging and discharging protection 3. With indicator lights, press and hold for 2 seconds before turning on. When turning on, all four indicator lights light up simultaneously 4. This product is a voltage reference that can be programmed with four common output voltages: 10.0 V, 7.50 V, 5.00 V, and 2.50 V 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, Weight: 0.11243575362 Pounds, Manufacturer: Reeatel