Headset with "firefly" in-use busy light at tip of microphone. This headset plugs into S12 base amplifier with modular (square) plug. This headset is the replacement for your existing S12 system only. It will not work properly with any other Plantronics systems.
IMPORTANT:This replacement part number comes only with the ear hook (not with the over-the-head headband attachment). If you are not specifically interested in the in-use busy light feature at the tip of the microphone, you can use the replacement headset for previous model S10 as a less expensive alternative which comes with both the headband and the ear hook. They are essentially the same except for the busy light feature.