Peregrine Ultralight Pack Cover 60-80L OD5080-MARMALADE Weatherproof cover for backpacks; a must have for keeping a pack and its contents dry in rainy conditions. 30D CORDURA Ultralite fabric delivers a desirable combination of qualities: durable, compact, lightweight, and waterproof. Double waterproof treatment with a siliconized outside and a polyurethane coated inside.