VOMLITE 8.4V to 5V USB DC Connecter Smart Voltage Converter Adapter for Bike Light Battery Pack to Cell Phone Build a backup power system to charge your phone and mobile devices. With two port for input and output. the standard USB port makes it a portable power pack for any mobile devices with 5V voltage and Android ports. Supply backup power to other mobile devices like mobile phone, bike computer and MP3. With a USB charging cable, you can charge the battery pack while you browse internet. And also with the USB port its use our battery of bike light to charge your mobile phones or other devices in emergency. Easy, Portable and Inevitable.