Vortex's highly-rated Viper HD binoculars feature upgraded HD glass and the latest in high-tech coatings. Viper HD binoculars are a diverse line of roof prism designs, ranging from 8x42 full-size to 12x50 super size. All are argon-purged to be totally fog- and waterproof, and are backed by Vortex's VIP unlimited lifetime warranty.