1 x motor + 6 Function (Fwd, Rev, AUX1 - 4) OO / HO scale DCC decoder with on-board MTC 21-pin plug complete with large stay alive kit. Switchable for digital DCC or Analogue DC running. The stay alive device has blue and a black wires which attach to the decoder - The blue wire is the positive / DC+ and the black wire is GND.