Overview: Plantronics S12 Telephone Headsets System offers hands-free convenience and comfort. Includes a 2-in-1 convertible Headsets for over-the-head stability or over-the-ear convenience, a noise-canceling microphone for superior sound clarity and the Firefly in-use indicator light that lets others know you are on the phone. Features: Plantronics telephone Headsets system In-use indicator lets others know when you're on the phone Noise-canceling microphone reduces background noise Headsets can be configured over-the-head or over-the-ear Connects to a single or multi-line telephone Not compatible with phones that feature the keypad in the handset or Cordless Phones Requires a telephone with an RJ-11 jack (not a 2.5mm plug) (amplifier plugs into the handset jack on the phone) Amplifier base Wire Headsets stand AC adaptor Silver and gray Package Contents: Amplifier base Headset stand Convertible 2-in-1 headset with noise-canceling microphone and Firefly in use indicator light AC adaptor User guideYBS