Unique patented neodymium magnetic system allows these glasses to come together at the bridge. The head band is form-fitting and wraps around comfortably to ensure a snug, comfortable fit. Putting them on is simple. Just place the band around your head and let the magnets draw together at the bridge. Want to take them off? No problem. Just pull the magnets apart and the glasses will hang comfortably around your neck. That way you know exactly where they are when you need them again.