Vortex Optics Raptor Porro Prism Binoculars 8.5x magnification and 32mm objective lenses, this Raptor binocular has a wide-angle, porro prism design that flexs to promote comfortable viewing for a variety of facial structures, wide or narrow. Fully multi-coated lenses transmit bright, crisp images with excellent color fidelity and clarity. Eyecups twist up for customizable eye relief while a right eye diopter accomodates for focal differences in your eyes. Rubber armor makes the Raptor durable while nitrogen purging gives you enhanced waterproof and fogproof performance in extreme weather conditions. The Raptor is a great fit for everyone in the family. Field of View: 390 feet/1000 yards|7.4 degrees Close Focus: 15 feet Close your right eye or cover the right objective lens with your hand. Look at the object with your left eye and adjust the center focus dial until the image is in focus. Close your left eye or cover the left objective lens with your hand and rotate the ring until the object is in focus. Blow away any dust or grit before wiping the lens. Use a can of pressurized air, soft camel hair brush, or acrylic optical brush. Gently remove smudges, fingerprints, and eyelash oil from the lens. Use a small amount of water or your breath to moisten the lens then wipe away smudges with a clean lens cloth. Isopropyl alcohol can help remove marks like fingerprints.