When backpacking, it's important to keep your gear nice and dry--no matter what Mother Nature throws at you. While your pack will shed light rain on it's own, when the weather turns really foul, you need a Rain Cover. The Kelty Rain Cover will protect your pack and the gear inside when unexpected weather hits. Using a combination of treated 600D Polyester Ripstop and 600D Polyester Oxford with 610D Polyester Cordura in the areas that need reinforcement, the Kelty Pack Cover will keep your gear dry. Also stays on your pack when the wind kicks up using an internal adjustable pull cord that secures the cover to your pack. Please note that when ordering the Medium Pack Cover, packaging may state the item is a Regular or a Medium.