These are Plantronics and Jabra/GN Netcom compatible headsets for SNOM 100, 105, M9, 200, 220, 300, 320, 360, 370, 710, 720, 760, 820/821, 870 IP Telephones. See the Snom IP Phone reference chart below for compatible headsets + bottom cable, handset lifter as well as Wireless Adapter (EHS). The corded headset adapter cable varies depending on the different SNOM phone models. It's very important that you pick the correct adapter cable with the headset (Plantronics or Jabra) - Jabra GN1200 use setting 4. Call us (877-999-3838) if you have any questions.