✓ COMPATIBILITY: plantronics encorepro 540, hw251 hw530 hw540 h81n hw251n hw261 hw301n hw720 hw291n h51 series headsets. ✓ DESIGNED FOR TRAINING: The Y-Splitter Adapter phone jack splitter is also a mic and headphone splitter, allowing you to use two headsets with one microphone. Use in office and call center training with your training headset. ✓ EASY TO USE: The Plantronics Y Splitter Adapter is an essential accessory for any Plantronics headset user, allowing them to easily connect two headsets to one phone or computer. ✓ INCLUDED ITEM: (1) GTW "Y" Splitter/Training Cable for Plantronics Headset, Global Teck Microfiber Cloth.