CliC Optical's unique patented neodymium magnetic system allows the glasses to come together at the bridge. The headband form fits around your head to ensure a snug and comfortable fit. 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. Now there's no need to separately buy chains. • Patented neodymium magnetic system • Adjustable temple length • Expandable headband • Color: TORTOISE • Strength: +1.25 Like new.... worn only once or twice, but I need a stronger magnification power!