Nument 35-50L Polar Backpack Rucksack Proof Water Dust Rain Cover Black Main material: nylon, elastic strip,Process: elastic strip tighten package the edge; Backpack cover for outdoor, set in the backpack appearance, with dust proof, water proof, anti-scratch, Prevent dampness,Sunshade,anti-fouling function, easy to quickly clean, Suitable for outdoor staff,traveler,athlete,student,fitness,walker,climber,explorer, Light, comfortable, durable