DOREMiDi MERGE-3 Guitar MIDI Host Box Adapter Converter With Five-pin Interface

Combine up to 3 MIDI input signals into 1 MIDI data stream, and output through 1 MIDI interfaces. 3 MIDI input, 1 MIDI pass-through output. Standard MIDI 16 Channels. Can be connect to PC or via MIDI to USB cable (Not included).

eBay