OUTAD Waterproof Backpack Rain Cover Extreme durability: made from rip-resistant polyester oxford fabric. Resilient design: Bottom of rain cover double sided to protect against soak-through and tears. Superior waterproof protection: guaranteed not to let rain into your backpack. Compact and portable: folds down and includes a drawstring bag for storage. Capacity and versatile: elastic design provides adjustability and select from 3 size options (15-35L, 35-55L, or 55-88L). Works for school backpacks and laptop backpacks too.