Amplifier and Headset Kit with convertible headset is compatible with most single-line, multi-line telephones. Allows PC headset connection for supporting multimedia applications. Connects to PC soundcard and other audio devices via two 3.5mm plugs (microphone and speaker). Offers microphone and speaker amplifications with adjustable volume controls. Quick disconnect mute function allows you to leave your desk without removing headset or disconnecting caller. Convertible headset can be changed for use with headband or over-the-ear. 7'4" cord. 4P4C RJ-11 telephone plug. Automatic power save function. Powered by two AA batteries (sold separately).