These Transmission (TX) and Receiving (RX) modules are additonally fitted to the gold plated PCB boards included in the AC031 Steering Wheel Conversion kit.This then adds the additional functionality via the steering wheel buttons/paddles for the Triptronic gear change. Please note that due to the Autobox ECU fitted in a Discovery 3, the Triptronic mode does not work in Manual (D1-D6) mode but does work in Sport mode (S1-S6)