Alpen Rainier ED HD Full-Size Binoculars - All Rainier binoculars push the limits of optical perfection. All optical components receive Alpen's exclusive UBX multi-layer coating for maximum light transmission. The extra large BAK-4 prisms are coated with over 60 layers of Alpen’s SHR metallic and PXA phase coatings to deliver the best brightness, clarity and color fidelity. Large diameter lens elements throughout the optical system provide enhanced field of view and eye relief for easy viewing. HD – High definition ED – Extra low dispersion optical system Waterproof UBX Fully Multi-Coated SHR Metallic Coated PXA Phase Coating A-lock diopter system BAK4 Optics Long Eye Relief Cleaning Pen Included Manufacturer Limited Lifetime Warranty