These Binoculars feature BAK-4 prisms and fully multi-coated optics for crisp, clear viewing. Large 42mm objective lenses gather plenty of light to ensure the viewing image is bright even in low light conditions. Superior close focus capabilities allow you to focus on objects as close as 6 feet in front of you! Close focus is particularly important for wildlife viewing because it allows one to view the details of a bird or animal out of nowhere.The JK-042 10x42mm close focus roof prism Binoculars are O-ring sealed and nitrogen purged making them waterproof and fogproof. Twist-up eyecups stop in three positions to provide optimal eye relief for all users. Large focus wheel turns smoothly for precise focus adjustments. Independent right diopter adjustment makes it possible to adjust the focus to allow for strength differences in each eye. The JK Series Binoculars are the ideal choice for hunting, birding, hiking or fishing.