Jabra GN Y-Training Cord Splitter- connects two Jabra headsets to a single phone to perform agent training, supervisory, coaching, multi-users on one call
Amazon.com: Jabra 265-09 Link 265 USB/QD Training Cable, Black : Electronics
GN Netcom Jabra Link 265 USB to Dual QD Y-Training Cable w/ Acoustic Protection | eBay
Amazon.com: Jabra GN Style Splitter Y-Training Cord (Observation- Live/Mute Version), Compatible with Jabra, Liberation, GN Netcom Headsets - Quick Disconnect - for Coaching, Supervising, Training, Monitoring : Electronics