Dependable spring-up cover works on both the Ocular (eye) or Objective (muzzle) end of your scope. The cover has tabs on both sides of the lid to be easily opened by right or left handed shooters. Blizzard lenses are made from Optical Grade polymers that achieve the most complete light transmission of all see-thru covers. See-thru covers give you the ability to make fast, offhand shots at fleeing game. Always open the covers for long-range shooting. It's very important to allow the complete spectrum of light to pass through your scope. Do not use reduction filters. The weather resistant seal and dependable spring system have been tested in a variety of extreme weather conditions. BC7020