Traxxas 6509R TQi 2.4 GHz 2-Channel High-Output Radio System, TSM Transmitter features model memory for up to 30 models with simple 2-button programming Interface and built in failsafe 5-channel receiver with Traxxas Stability Management (TSM) accepts optional telemetry sensors Optional #6511 Wireless Module allows visual access to real-time telemetry and customizable dashboards via Traxxas Link app Optional Traxxas Link wireless module pairs TQi with Android 4.4+ or Apple iOS 4.3+ platforms Direct Sequence Spread Spectrum Technology (DSSS) uses only 4 AA batteries