size Medium: height 38CM thickness 15CM width 29CM Large: height 42CM thickness 19CM width 32CM weight Medium: 0.53kg Large: 0.58kg Material: Nylon Color: blue, red, rose red, cyan There are safety reflective strips, and there are reinforced stitching at the triangle of the bag, the handle, and the connection. LARGE CAPACITY & ORGANIZED: one main compartment roomy for daily necessities, such as clothes, notebooks, portable charger, etc. The front compartment has many small pockets, as well as pen pockets and a keychain design to keep your things organized and easier to find. DURABLE MATERIAL: Made of water resistant and durable polyester fabric, high-density nylon lining for better tear resistance, the heavy duty backpack with metal zippers ensures daily long lasting use. Serve you well as professional school backpack COMFORTABLE: With a comfortable padded back design and thick and soft multi-panel ventilated pads, the big backpack gives you great back support. Breathable and adjustable shoulder straps relieve shoulder pressure to reduce discomfort in long packs. The backpack for boy gril will be a good partner for travel, school, work, business, etc