Monaural headset for desk phones Noise-cancelling microphone filters background noise Pivotable boom rotates through 350 degrees for wearing flexibility on right or left ear and precision microphone placement ActiveGard technology protects you from acoustic shock by preventing sudden sound surges Connecting the headset requires a connection cable OR amplifier Neither option is included and both must be ordered separately. Please note that the required connection cable varies by phone. Please specify your phone model to enable us to provide the correct cable. The amplifier does not require an additional connection cable.