The Plantronics S10 Telephone Headset System offers both a convertible, noise-canceling headset and amplifier to bring hands-free convenience to corded phones. The system is compatible with most single- or multi-line corded phones, and includes a variety of features to enhance communications. These include transmit and receive volume controls, so you can set the sound level that is most comfortable for them, a contemporary, ergonomic design for easy accessibility and a visual indicator that shows if the system is in headset or the handset mode.