... protection, etc function.Easy to use:1, Charge the power bank 1-1, use USB cable & a USB ... when full charged. 2, How to know the power bank's electric quantity? 2-1, press down switch button ... Attention:1, before using, please do charge the power bank over 9 hours to extend it's lifetime ... compatible with digital device. 3, Do not disassemble the power bank without authorization. Please do not striking it ...