Available in apertures ranging from a compact 26mm that slips easily into a coat pocket to an impressive 56mm that gulps in light, Wings waterproof binoculars have fully multi-coated optics and premium BaK4 prisms that produce bright, high-contrast images even in twilight conditions. Designed with versatility in mind, these binoculars have an open bridge for steady gripping and feature twist-up eyecups to comfortably accommodate observers with or without eyegl. In addition to being waterproof, Wings binoculars have rubber armoring for protection against minor bumps and are purged with an inert gas to prevent internal fogging. USA Limited Lifetime Warranty when product is registered within 60 days of purchase. FEATURES Waterproof BAK4 Optics Long Eye Relief Fully Multi-Coated Lightweight and ergonomic open hinge body design Twist up eye cups