For HTC one MAX Backup Battery Charger Case Cover Power Pack with Stand and front cover 4200mAh Black Unique, fashionable and high-class sliding design for HTC one MAX Act as an extra battery, power station or protection case for HTC one MAX Non slip and comfort gripping design, provide ultimate protection from scratches and other minor damages for your HTC one MAX A perfect emergency backup when the internal battery of your device is drained on the go ON/OFF Button for optional power output control - save power when it is not in use