Nikon's Action EX Extreme All Terrain Binoculars are designed to appeal to optics users who value tough construction and reliable optical performance under even the most extreme conditions. Nikon Extreme binoculars feature an all-metal chassis with lens fittings housed in a tough, lightweight polycarbonate body shell. The 12x50 EX is nitrogen-filled and O-ring sealed for total waterproof, fogproof and shockproof performance in any environment. The binocular bodies are ergonomically shaped, tripod adaptable and rubber coated for a non-slip grip, whether wet or dry. The Action EX series binoculars each feature a unique, click-stop eyecup design that not only delivers long eye relief, but also allows for variable eye relief that is customisable to the user's own eyes and eyeglasses. The binoculars are central focus with a diopter control to correct for normal right/left eye vision imbalance.