Dependable flip-up covers work on either ocular (eye) or objective (muzzle) end of your scope. The covers have spring-loaded tabs on both sides of the lid that allow the scope covers to silently flip open out of the way. Blizzard lenses are made from optical grade polymers that allow the most complete light transmittance. See-thru scope covers give you the ability to make fast, offhand shots at fleeing game.