Vortex Optics Crossfire Roof Prism Binoculars 8x magnification and 42mm objective lenses, this Crossfire is a quality, performance driven binocular perfect for your next hunt. Fully multi-coated lenseses promote excellent light transmission and clarity for impressive views. A wide field of view and enhanced depth of field help you quickly find what you were looking for when scanning your environment. Twist-up eyecups, a smooth center focus wheel, and right eye diopter give you precise functionality. Rubber armoring with clean, sleek styling provides a durable non-slip grip. With nitrogen purging, you will be ready for all weather conditions with fogproof and waterproof barrels. 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.