Traxxas 6550 Telemetry Expander for TQi Radio System Telemetry Expander supports up to six plug-and-play "smart" sensors in addition to the three standard sensors Automatically detects and recognizes the installed telemetry sensors for easy setup Adding the optional GPS Module (#6551) gives you the ability to accurately track real-time speed Provides telemetry on Traxxas Link app in vehicles equipped with Traxxas Link TQi transmitters and receivers Waterproof case keeps the expander safe from the elements