Built around Leupold's Twilight Max HD Light Management System, the BX-4 Pro Guide HD binoculars boast un-paralleled brightness, edge-to-edge clarity, and advanced glare management elements; helping you see more details in less light. Their ergonomic open-bridge design is comfortable for extended glassing sessions and delivers key weight savings for those long backcountry adventures. Features Include: 100% Waterproof and Fogproof, BAK 4 Prisms, Central Focus Dial, Ergonomic Design, High Definition, Tripod Read, Twilight Max HD Light Management System, Twist Up Eyecups.