Amazon.com: USB Headset Training Adapter | USB Y-Cord for Plantronics QD Compatible Headsets to Computer via USB - Connect Two Compatible QD headsets to one USB Port : Electronics
Amazon.com: USB Headset Training Adapter for Plantronics Headsets : Electronics
HDI Wireless Headset Training Adapter - Headsets Direct
Duplex Headset Mate Training Adaptor
Plantronics 27019-03 Headset Y Training Cord with Mute For HW530 HW520 HW510 H41 | eBay
Plantronics Y Training Cord Headset Splitter (27019-03)
USB Buddy Training Adaptor
Headset Quick Disconnect Cord Y Adapter Trainer Cable for Training Center,Compatible with Plantronics and Same QD headsets|adapter manufacturer|phone headset adapterphone blue - AliExpress
Poly/Plantronics Y Adapter Training Cable 27019-03