Sennheiser Electronic Corporation (SEC) is the U.S. wholly-owned subsidiary, with headquarters in Old Lyme, Connecticut. Premium contact center headsets with exceptionally clear and natural sound. Sleek design that’s built to last. And attention to the smallest detail. With user-focused features like the patented ActiveGard®, which protects you from the potential danger of acoustic shocks, Sennheiser has a headset for your every application.