Features: Perfect for embedding in portable electronics like Bluetooth-compatible earphones, smart wearable without occupying much space. Equipped with internal comparator featuring hysteresis, this module prevents frequent LED flickering during fluctuations, delivering power display during charging/discharging cycles. Specifically designed for 3.7-4.2V single cell batteries, it perfectly serves power monitoring needs for mobile power banks, wireless earbuds. The green yellow red LED visually indicates battery across four precise (3.4-4.2V), allowing power assessment without complex display. Ideal for compact electronics including smart watches and health devices like glucose meters, providing space saving accurate battery monitoring with simple LED visualization. Specifications: Component:ABS Size:Approx.4.5x9.1mm/0.17x0.35inch Package Includes: 2 Optional Package: Package 1 Include:5Pcs Power Display Module Package 2 Include:10Pcs Power Display Module Package 3 Include:20Pcs Power Display Module note: 1.Please allow 1-2cm errors due to manual measurement, making sure that you not mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual of the item.