Sennheiser SC 660 USB CTRL (504555) - Double-Sided Business Headset | For Unified Communications | with HD Sound, Ultra Noise-Cancelling Microphone, & USB Connector (Black) Double-sided headset (sc 660), HD voice clarity Connect to a Softphone via USB Active Guard technology protects against acoustical shock Ultra noise cancelling microphone Call control unit answer/end calls, control volume, Redial and reject incoming calls Premium dual-sided wired headset optimized for Microsoft Lync, with built-in call control unit Comfortable fit that lasts all day and a solid sense of quality Century is built to sound superb, look stunning and outlast the competition Conversations are crisp and clear for speaker and listener, even in noisy environments Century is crafted with high-end materials to ensure maximum durability and design quality Stainless steel hinges, brushed aluminum parts and Kevlar cables defend headset against everyday use Century is designed for long-hours use throughout a working day-that means everything focuses on wearing comfort Large leatherette ear-pads to the unibody headband construction for maximum strength at stress points