The Leupold Alumina Flip-Up lens covers offer you maximum protection for your most valuable possession, your Leupold scope. The Alumina flip-up lens covers are held shut with a magnetic catch. They feature a teiple O-ring seal for maximum protection from moisture and dust. The machined aluminum construction is durable and lightweight. Each cover is sold individually and is intended for Leupold scope made in 2004 and later.