The REDLITHIUM? USB charger & portable power source is designed to get through the day by charging your REDLITHIUM? USB batteries and electronic devices on the go. Check the remaining charge of your REDLITHIUM? USB battery with the LED fuel gauge, by pressing the lighting bolt button. The compact size is small enough to fit in your pocket or tool belt to conveniently top off the batteries of your mobile devices on and off the jobsite. Both REDLITHIUM? USB battery and portable power source and charger covered under 2 year warranty.