The battery is a 300mAh standard battery, with a voltage of 3.7V and model number 14250. The charging and discharging interface is micro-USB; input voltage is DC 5V. The device should be fully charged every two months when not in use. It features built-in charge management and overcharge/over-discharge protection. Do not reverse battery polarity. The output interface is a 2mm banana socket, with an SMA output interface for calibration. Calibration is performed using an HP3458A 8.5-digit multimeter after full preheating. Re-calibration conditions, date, and calibration values are recorded on a label attached to the unit—please retain this label. Press and hold the power button for 2 seconds to turn on. Upon startup, all four indicator lights illuminate simultaneously, then output 2.5V reference voltage. After startup, short press the button to cycle through output voltages: 2.5V → 5V → 7.5V → 10V. Long press for 3 seconds to power off; indicator lights turn off immediately. Material: Plastic Color: Yellow Package Contents: 1 × Reference Module Note: Due to lighting conditions and display differences, the actual product color may vary slightly from images. Measurement tolerance: ±1–3 cm.