A wide range of applications Simple operation with one-key backlight on/off control Intelligent detection with prompt function Made from ABS retardant environmental protection material, high temperature resistance Lightweight and compact design with built-in lithium battery and portable belt Integrates multiple functions in a professional LCD industrial design Simple operation with backlight function and long-lasting energy efficiency HTN wide viewing angle LCD with green backlight Equipped with 3.7V/1000mAh standby lithium battery and Type-C charging interface Capable of measuring 18650 lithium batteries Measures voltage and internal resistance of AA/AAA alkaline batteries Results displayed clearly on LCD screen Dimensions: 156 x 63 x 36mm Calibration instructions: After removing the back panel, gently push up from the front LCD position and carefully disconnect the red wire on the back Apply a standard 5V voltage between V+ and V- Press the power button to turn on the device and verify normal voltage display Remove the battery, short-circuit the two designated points, then reconnect the battery to initiate automatic calibration Once calibration is complete, reassemble the device Color: Black Material: Plastic Package Contents: 1 x Digital display tester (Note: Product appearance may vary slightly by batch, but functionality remains unchanged) No other items included Note: Lighting and display differences may cause slight color variation from the actual product. Measurement error allowance is +/- 1-3cm.