Sennheiser CIRCLE™ SC 230 USB CTRL II (single-sided) and SC 260 USB CTRL II (dual-sided) headsets, feature an in-line call control unit and work seamlessly with all UC platforms. With Sennheiser Voice Clarity, a noise-cancelling microphone and a lightweight, ergonomic design for all day use, they are the perfect tools when clear communication and long-term user comfort are crucial to the job in hand.