Train Control Systems TCS 1525 HO WOWSound WOW121 Steam Sound & DCC Control Decoder 21-Pin Connector NIBTrain Control Systems TCS 1525 HO WOWSound WOW121 Steam Sound & DCC Control Decoder 21 Pin Connector NIB 21 Pin Interface 6 Functions This 21 Pin, 6 function, WOWSound decoder includes all of the amazing features and incredible performance found in a WOW101 in a shorter form factor with the popular 21 Pin plug. This decoder does not include a Keep Alive device, but pairs wonderfully with one of the motherboards below (all of which include a built in