Mini Battery Capacity Indicator Power Level Display 1S 2S 3S 4S 5S 6S Li-ion 12V Lead Acid with Reverse Connection Protection Features: 1. Use of high-quality materials, durable 2. Compact size, exquisite appearance 3. Ultra-thin power display, 5 LED indicators, display more intuitive 4. With reverse connection function, even if the positive and negative connection will not burn 5. Use a wider range of lithium batteries, lead-acid batteries, lithium iron phosphate, electric car battery electric equipment can be used Specifications: Overall dimensions: 21.7mm diameter, 3mm thickness Use Method: 1. The positive and negative terminals of the display board and connected to the positive and negative ends of the battery under test, lightly press the red button with your finger, the ED light will be lit to show the real-time battery power 2. Release the finger, the LED light is delayed for 3-10 seconds and then extinguished, no power consumption at all when static Package Included: Round power indicator board * 1