The telemetry trigger magnet holders secures the trigger magnet to the spur gear to provide real-time RPM and speed data when combined with an RPM sensor, TQi radio with Traxxas Link^™ Wireless Module, and the free Traxxas Link app for your mobile device. Includes smaller 1/16 scale magnet holder and larger 1/10 scale magnet holder with magnet, 3x8 mm screws (3) and 3x10 mm screws (3).