The Gladiator 7-21x40 Zoom Binoculars by Barska feature a powerful 7-21x zoom that allows you to adapt the zoom for whatever application you're using them for. The Gladiator's ruby lenses help to minimize UV glare, and large 50mm objective lenses for increased light transmission under the darkest conditions. The zoom thumb lever makes smooth zoom adjustments quick and easy, allowing you to zoom to a higher magnification to capture finer detail. The Gladiator 7-21x40 Binoculars feature a conivenient center focus system for dynamic adjustments while looking throughout the binoculars.