Instructions: This USB cable lights up red when connected to the power supply, turns off when charging, and lights red when fully charged. Lightweight, portable, reliable, and powerful USB charger. Function: Intelligent charging management IC is configured inside the charging line, which can accurately charge the 3.7V lithium battery. It will stop automatically when fully charged without overcharging. Plug and play. As long as the USB is connected to the device, it can be charged normally, and other work can be done during the charging process. The charging cable is equipped with intelligent charging management IC, which can accurately charge the 3.7V lithium battery. It will stop automatically without overcharging. The full-charge cut-off voltage is 4.23V, making reasonable use of the characteristics of lithium battery and extending the service life of lithium battery. Charging indication: Plug in the power supply, the red light is on; the red light turns off when the battery is connected and charging; the red light turns on when fully charged. Scope of application: Polymer lithium battery, cylindrical lithium battery, digital lithium battery, remote control aircraft lithium battery. The USB battery charger cable with plug, output 3.7V 500mA, is suitable for 3.7V (1S) LiPo battery. Note: For LiPo battery only, do not use for Ni or Ni-Cd battery. Specification: Material: ABS Plug model: USB Type: 3.7V USB charging cable Input: DC 5V 0.5-2A Output: DC 4.2V / 500mA Standard voltage: 4.2V Color: Black Size: One Size Cable Length: 630mm Quantity: 1 Piece Note: Transition: 1cm = 10mm = 0.39inch No retail package. Please allow 1-3mm error due to manual measurement. Please make sure you do not mind before purchasing. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package included: 1 x USB Charging Cable Plug Charger