JABRA Evolve 6393-829-209 40 Uc Monohd Audio, Microphone Design: Flexible Boom, Driver Size: 28.00 mm, Cushion: Leatherette, Earpiece Design: On-Ear, Listening Mode: Monaural, Speaker Frequency Response: 70 Hz to 20 kHz, Host Connection: 1 x 3.5 mm/1 x USB Type-A, Rated Power: 10 mW. The Jabra Evolve 40 UC Mono Headset is a headband-style headset comes with a control unit for easy operation as it allows you to use functions like volume and mute and the ability to end and answer calls.