This is a one-off hack to retrofit a genuine Western Electric Dreyfuss Telephone Handset into a full fledged Bluetooth handset. A single button at the center of the mouthpiece controls all the functions (pairing, answering calls, etc.), while a blue and red LED indicator glows from within. The handset recharges via USB and lasts 6 hours in active talk-time and 110 hours in standby mode.