Tinksky Foldable Outdoor Camping Hiking Waterproof Dustproof Travel Backpack Rucksack Rain Cover Protector 15L-35L (Black) Material: durable soft nylon. Size: Suitable for all 15L-35L of backpacks. Waterproof and dustproof nylon fabric, to well protect your backpack or school bag from rain, water, dust and other damaged while traveling, hiking, camping or doing other outdoor sports. Ultra-light and super flexible, can be adjusted to suit for your backpacks. Portable and foldable design for convenient to carry.