SC 635 USB-C and SC 665 USB-C are premium wired headset with connectivity to PC or mobile devices using USB-C or 3.5 mm jack. Designed for modern contact-center-agents requiring outstanding sound quality, durability and added mobility. Optimized for UC and Certified for Skype for Business. Outstanding sound for clear calls With enhanced music audio performance, Sennheiser Voice Clarity and ultra noise-cancelling microphone Increased mobility with flexible connectivity With both 3.5 mm jack and USB-C connectivity High-quality design crafted for perfection With brushed aluminium and stainless-steel components and unibody headband construction for maximum strength at stress points Convenient and seamless call handling With in-line call controls when connected via 3.5 mm jack or USB-C Sennheiser Voice Clarity If you are working in a noisy enovironment, you will benefit from the Voice Clarity technology in Sennheiser Century™ headsets. With an ultra noise-cancelling microphone and detailed sound, every word comes through crisp and clear. It's as if you're having a face-to-face conversation.