Joy Walker Waterproof Backpack Rain Cover for (15-90L), Upgraded (Anti-Slip) Buckle Strap & Strengthened Layer for Hiking Camping Traveling Cycling UPGRADED BUCKLE STRAP: keep backpack cover in position, no more sliding off. FOR BACKPACK (15-90L), Please select size and color to see the dimension range or watch the 6th picture left INCREDIBLE DURABLE: Made of 300D Nylon features wear-resisting and durable DOUBLE CONSTRUCTION: External fabric is rip-resistant that protecting backpack from scratch, dirt, sand and internal is waterproof coating that keep it from water, rain, fog and snow. COMPACT: Each backpack cover comes with a velvet pouch that easily to storage and not take much place VIP CUSTOMER SERVICE: FREE exchange size if not match without RETURNING, FULL refund if cover slide down without RETURNING