Air Telemetry Flight Pack Voltage Sensor: D. Ultra by Spektrum

Compatible with Android 4.4 and up or Apple iOS 4.3 and later platforms Use with the powerful Traxxas Link app, available on Google Play and the App Store View real-time telemetry with optional sensors Bluetooth low energy Easy and simple device pairing Powered by TQi transmitter Integrated into transmitter body Quick and easy installation, installs in minutes Traxxas Link Wireless Module included with select Traxxas vehicles