Key benefits Ultrathin battery power display with five LED indicators for a clear, ataglance readout of realtime battery power. Simple manual operation: press the red button to illuminate the LEDs and view the current charge level. Low power in static state: no power is consumed when the display is not actively used. Easy integration into compact projects thanks to its slim form factor. What it is and how it works Ultrathin electricity display featuring five LED indicators to show battery power levels. To test a battery, connect the display board to the battery by wiring the positive and negative terminals to the battery's positive and negative ends. Press the red button briefly with your finger; the LED indicators light up to show realtime battery power. Release the button; the LED indicators stay on for about 35 seconds and then turn off. Static operation consumes no power, making it efficient for repeated use without draining the battery. Specifications and operation notes Battery type: 3.7V lithium battery Full charge voltage: 4.2V Display: 5 LED indicators Activation: red button to illuminate the indicators Idle behavior: LEDs turn off after 35 seconds when the button is released Power behavior: no power consumed during static operation Form factor: ultrathin design for easy integration Use scenarios Scenario 1: Preuse check for 3.7V Liion batteries in RC devices such as drones, cars, or boats to confirm sufficient charge before operation. Scenario 2: Quick status check of batteries in portable electronics and power banks to determine if a recharge is needed. Scenario 3: Routine battery health checks for small electric tools or gadgets, ensuring reliable performance in daily tasks. Compatibility and connections Designed to connect to the positive and negative terminals of the battery to be tested. Suitable for batteries with accessible positive and negative terminals that you can wire to the display.