Vortex Optics Viper HD 2018 Roof Prism Binoculars 10x magnification and 42mm objective lenses, the 2018 Viper HD is a high-end, full-size yet compact binocular that is suited for any hunt. An easy-to-grip, rubber armored chasis with perfectly placed thumb indents provides superior ergonomics. A high density optical system delivers exeptional resolution and edge to edge clarity. XR anti-relfective lens coatings give bright, full views even in low light situations. A locking, right-eye diopter tailors each barrels' focus to your eyes. The smooth, center focus wheel provides fine focus control and quick sharp views. Twist-up eyecups rest comfortably against the face and provide customized eye relief. Argon purging and o-ring seals provide a lifetime of waterproof and fogproof performance. Ultra-hard, scratch resistant armortek protects the exterior lenses from scratches, oil, and dirt. In the field, you should have no trouble reaching them at a moments notice with the included GlassPak Chest Harness providing comfortable, protected, strain-free, all-day carry. 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.