Features: Real-time monitoring: It can accurately monitoring the battery power, helping users to keep abreast of the device's usage time and remaining power. Energy saving: It can help users manage power more effectively and avoid sudden power loss of the device due to power depletion. Extend battery service：By regularly checking the battery level and using the power wisedly, helping to extend the battery use. Increase portability: Helping users adjustments or recharging when need, increasing the portability of the device. User-friendly: Provides intuitively display of the power, enabling users to easily understand the battery status of the device, facilitating operation and use. Specifications: Item：Digital Battery Tester Component: Plastic+Electronic For AA/1.5V/3.0V/9V 18650 Various Batteries Size：about 110x58x25mm/4.33x2.28x0.98in Package Includes: 1PC Digital Battery Tester note: Due to the different light effect, the actual color the item might be slightly different from the color showed on the pictures. Please allow 1-2cm measuring difference due to manual measurement.