Features 1. Detail Design: Chest fixed buckle to reduce bag shaking and prevent shoulder straps from slipping. Back fixing strap, pull rod insertion strap for fixation, no need to carry on the body. Breathable heat dissipation, reinforced with hollow grooves 2. Material: shock-absorbing and compressive computer seat, using a soft cotton layer to prevent scratches and shaking. The wrapping material is made of ultrafine fiber synthetic leather and fabric. 3. External USB Charging Interface: The backpack has a built-in charging data cable. Simply connect the mobile power supply to the backpack data cable, and the USB interface can be used for charging. 4. Waterproof And Durable: This bag is made of splash resistant fabric, and when rainwater hits the bag, water droplets will automatically slide off. 5. Large Capacity: The expansion package can have a capacity of up to 36L and is in a resistant form. The bag also has a hidden pocket for safe storage of the phone wallet. Specification Material: Oxford Cloth Color: Black, Blue Size: 44 x 30 x 27 cm Weight: 1000 g Package Include: 1x Expandable Backpack Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.