Combination 2400mA USB charger and 3-LED battery monitor, with vehicle battery protection. Vehicle battery protection: USB output turns off 3 hours after engine stopped or when vehicle battery charge level is less than 50%. 3 LED battery monitor (when USB output off) – battery status is displayed every 5 seconds. 12V input through an industry standard SAE 2-pin connector. 5V 2400mA true output. Unique seal and cap design for USB socket ; use any USB cable, seals when inserted. Short circuit, overheat, over-voltage protection. Premium USB product designed by TecMate. 3-year limited warranty.