The Flip-up Transparent Rear Lens Cover slides over the rear end of the Acro P-2 sight for added lens protection. The cover is durable rubber and the lid has a spring-loaded flip-up mechanism and snap closure. The cover easily flips open and out of the way effortlessly when needed and closes tightly with a snap. The use of lens covers protect lenses from scratches and keep the optic free from dust and debris during transport and storage. The flip-up function provides fast access to rain free and clean lenses when sight is in use, once it's open the lid stays up until it's manually closed again.