TCS 1674 EU821, 8 Function HO Decoder with MTC21-Pin Connector
SBS4DCC - The Infamous 21MTC Interface Connector
1676 8-function decoder for HO-Scale locomotives equipped with a MTC21-pin connector and Keep-Alive wires and connector – #TCS-EU821-KAC – Litchfield Station
DCC Train-O-Matic Mini MTC21 Decoder with SUSI Connector (M21S) 9145386315766 | eBay