Plantronics 900MHz Cordless Phone Amplifier with DuoSet™ Convertible Headset 900MHz Cordless Amplifier with DuoSet™ Headset • Up to 150-ft. range from base unit • Six-hour talk on rechargeable battery • Adjustable receive/transmit volume controls • Convertible headset fits over the head or ear Answer your phone when you’re away from your desk! Connects to single- or multi-line corded telephone. Superior sound. Includes mute, power on, talk and charge indicator lights.