Plantronics Y Trainer.. Product # 27019-03.. The Plantronics 27019-03 Y-training cord / Y-splitter cable allows 2 headsets to operate with one amplifier for training / monitoring purposes. Both headsets can listen, but only one headset will have a live microphone. The other microphone is muted. The red toggle switch allows the supervisor to control which microphone is live and which is muted... 27019-03