BlueField Backpack Rain Cover Outdoor Water Resist Pack Covers for Hiking Camping Traveling Compared with ordinary backpack rain cover with elastic band fastener,this one adds the extra buckle to fasten the backpack more steadily. Not only it's keep the backpack dry,but also it keeps out dusts,intense sunlight,frictions,etc. Adopt 300D polyester oxford Material, twice water resistance PU. and paid more attention to strengthen the part of raincovers get ripped easily; durable and wear-resisting Small Size, fits for 15-35L backpack; Middle Size, fits for 35-55L backpack; Large size,fits for 55-80L backpack With high quality waterproof materials in the sewing gaps,work effectively in the rain.