The battery case was charging and protecting double function, well-made hard case with 360 degree protective bumper design, protect your iPhone from scratches or other daily wear and tear. Ultra Slim: Specially design for your phone, No Excessive Bulk, Convenient enough to fit your pocket or in your hand.it's portable charging anytime and anywhere. perfect for traveling, camping, business trip or other outdoor occasions. high-quality polymer batteries and safe circuit diagram design, internal chips to protect your smart phone from overheating, short-circuiting, over charging, and discharging. Large Capacity & Smart LED Indicators: Add 100% Extra Battery Life to your iPhone , and the 4 LED Power indicators let you know the status of the Battery Pack (0--25%--50%--75%--100%) The top of the battery case is soft rubber, making it easy to install and remove. Carefully insert the battery connector to the charging interface, and press cellphone into the case, easy to charge your phone by pressing the power button.