Oxking Mountaintop Outdoor Hiking Climbing Backpack Daypacks Waterproof Mountaineering Bag M5811 Shoulder Bag 35L-45L Unisex High-capacity Travel Bags Loptop Bags Multi Colors (Grey, 45L+5L(expand)=50L) large capacity of 40L-45L Large front pocket, multiple zippered side pockets, and multiple elastic bands Supwer carrying-CR professional adjustable weight decompsition sytem, rainproof design Powerful Bear Breathable System, the heat could quickly spread out, avoiding the embarrassment of sweat, also it's more comfortable for your back Safety Belt-carrying back system uses specially thickened waist made of sponge, while better protecting your waist, your weight decomposition in travel, and it the waist band covered with mesh, it's more comfortable for your pack