Binger 10-30x50 zoom binoculars BK 7 Porro Prism Coated Optics Promotion 10-30x zoom for a wide range of outdoor activities, including birdwatching, nature observation and hiking Rubber armour for shock-resistance and a firm, comfortable grip Coated lenses for brighter images and porro prism for maximum light transmission Smooth zooming with finger-tip zoom control Large focus wheel for fast and find adjustment