Vbiger Large Capacity Lightweight Travel Water Resistant Backpack / Mountaineering Hiking Daypack (Dark Blue, 40 L) Water resistant nylon fabric, providing long-lasting performance with minimal weight. Ergonomical air diversion system and breathable mesh on the back for pressure reduction. 40L capacity, much larger than other hiking backpack, roomy enough for your hammock, clothes, towel, journal, and other outdoor survival supplies, etc. Multiple straps on the lateral pockets, keeping your bottles/umbrella strong and tight. Adjustable and breathable padded shoulder strap to meet different requirements for both men and women.