Leupold BX-4 Pro Guide HD Binoculars is a great option if you need optics for viewing during early predawn hours or if your observation extends well past the dusk. The binocular has an open bridge layout and a host of features. The list starts with High Definition optics with calcium-fluoride lenses for extreme clarity regardless of the magnification levels. Next is Twilight Max Light Management system for crisp, high contrasting images along with phase coated BAK 4 Prisms for high resolution. The BX-4 Pro Guide HD also has a fully multi-coated lens system to enhance light transmission and balance colors for maximum contrast, and deliver maximum brightness, clarity, contrast and color fidelity. While the ergonomic design ensures the binoculars fit well in your hands, the lightweight, aircraft-grade, aluminum housing with rubber armor coating promises all day viewing comfort and a positive grasp.Also in the offing are twist up eyecups and ample eye relief for comfortable extended viewing, special mechanical structures to control glare, and built-in binocular pouch with side pockets for keeping necessities. In addition, the Leupold BX-4 Pro Guide HD binoculars are totally waterproof, fogproof and extremely rugged, and render a perfectly round exit pupil with almost no edge distortion.