Plantronics' CT12 2.4 GHz DSS Cordless Headset Telephone (analog, single-line) is an ultra-compact single-line telephone, offering hands-free convenience and comfort. Includes convertible 2 in 1 headset for over-the-head stability or over-the-ear convenience, a noise-canceling microphone for superior sound clarity and Firefly, the unique in-use indicator light that lets others know you are on the phone.