1. Ultra-compact design with small and lightweight features, crafted with ABS+PC fireproofing materials. 2. The plug is flexible, can be 90 degrees swing. 3. With LED screen, to show car battery voltage & prevent your phone from overcharge. 4. When the voltage is below 11.8V or 18V - 23.8V, the buzzer alarm will automatic ring. 5. The current will be shown on the screen automatically. 6. With intelligent chip inside, the current will automatically share while using. 7. You can charge 2 USB devices at full speed simultaneously.