E For Those Who Can'T Tell The Difference.. The Aeeeee A Symphony. The Ultimate Nylon lining ? UPGRADED BUCKLE STRAP: keep backpack rain cover in position, Prevent backpack cover from sliding off. FOR 40-50L BACKPACK: Length(9.8-13.7"), Width(5.9-9.8"), Height(21.6-25.5") ? HIGH-LEVEL WATERPROOF: Our backpack cover is made of 210t TAFFETA mixed material features wear-resisting and durable, support 8000 mm water pressure. ? 4-LAYER CONSTRUCTION: External fabric of backpack cover is rip-resistant that protecting backpack from scratch, dirt, sand and internal is double waterproof coated layers that keeping off water, rain, fog and snow. ? COMPACT: Each backpack rain cover comes with a pouch that easily to storage and not take much place ? VIP CUSTOMER SERVICE: FREE exchange size if backpack rain cover not match without RETURNING, FULL refund if your backpack cover get ripped and get a new one.