Vortex Viper spotting scopes feature 50-, 65- and 85-mm objective sizes, angled and straight configurations, all with HD glass. All Viper spotting scopes are argon-purged to be completely fog- and waterproof. Viper scopes come with a zoom eyepiece that is 11-33x on 50mm bodies, 15-45x on 65 mm, or 20-60x on 85 mm.