The West Wolf Adult Waterproof 50l Backpacks for Hiking Camping Traveling Outdoor with Thick Shoulder Straps (Black) nylon-mesh Strap, back pad using three different materials in combination: first layer is a grid design (more breathable), the second layer is a sponge, a third layer is EVA material (shock resistant) The main compartment of the backpack has sponge interlayer, which able to carry 14-inch computer (Max.14.3*10.2*1.5 inchs) High-quality zippers, but also water-resistant Strengthen key parts to increase the stability of the backpack Chest strap sliding buckle: You can adjust the heights of chest strap, in order to fit the needs of different heights