[Smart Fast Charger-VOLTAGE MONITOR] The car cigarette lighter usb charger ensures that your device is charged efficiently and consistently. iPhone car charger / Samsung Galaxy car charger is built with overcharging, over current, over-voltage, temperature control, and short circuit protection to protect your device's battery from overcharge damage. [Flexible Retractable Design] The retractable car charger pulls out the cable within the 80cm range, and it retracts back inside automatically for storage, keeping it clean and tidy without cable entanglement, and facilitating convenient control and usage.