Remotes SKR433 Components out of the series SKR433 are compatible with each other. Remote Transmitters SKR433: MIDI-Transmitter SKR433-3 MINI-Transmitter SKRJ433 Wall-Transmitter SKR2W433 Digi Pad SKR4C433-1 MIDI-Transmitter SKR433-1 Digi Pad SKR4C433 MIDI-Transmitter SKR433 SKR433 Remote-Receivers: MINI-Receiver, 24V MINI-Receiver, 230V