A5 2.4G Wireless transmitter attachment:•Battery Specifications : 3.7V 60mAh Li-Po •USB Charging port input : DC 5V •Size : 86.7 x 19.8 x12.8 mm •Weight : 15 g Instructions:•ALIGN A5 transmitter attachment is developed for smart phone (iPhone、iPad、iPod touch) to control TREX-100 and ALIGN Flight app need to be installed on your smart phone. •ALIGN Flight is the control interface for your T-Rex 100 helicopter, which can be downloaded and installed to your iPhone (and iPod Touch, iPad) through iTunes by searching for ALIGN Flight. •The control interface mimics the rc controllers with two sticks that controls the helicopter"s movements. The stick modes can also be changed to one of the 3 settings. In addition, helicopter control can be done through iPhone"s motion sensors. Accessories:•A5 Transmitter x 1 Model: HERA5001**NOTE** This item charges via a USB port on it"s side. You use the USB cable that came with your heli to connect this to your computer"s USB port for charging. It does not come with a separate charger.