PRODUCT MATERIAL AND DIMENSIONS : Made of durable eco-friendly waterproof nylon fabric load of bearing 40kg with capacity 50L(23.6 x 11.8 x 7.8 inches).It meet size requirements for most airlines, enough room for 3 or 4 days trips. BACKPACK CAPACITY : 45L main capacity with an extendible 5L top lid for more essentials. An extended collar with drawstring at the top can expand the trekking backpack and increase the main compartment by 5 liter. MULTIPLE COMPARTMENTS : Features a classic shape with several pockets for storage and organization. This backpack has a roomy main compartment, two front zipper pockets to hold small accessories, and two side pockets for water bottles or umbrellas. 8 STAGE SIZE-ADJUSTABLE : For tying up your pack or hanging sleeping bag, mat, hammock, tripod, and other gears.With increased carrying capacity, the wide, adjustable shoulder straps with chest strap ensure good load distribution, while the padded back of the backpack ensures stability. A RAIN COVER INCLUDED : The rip-stop polyester material can prevent the water from sipping into the bag.If the heavy rain comes, then rain cover works.