-piece trolley school bag for middle school students with multi-layer breathable backpack -4The product is shipped based on the color or size of the main image of the product page. ur: -4product information:Product name: school bagMaterial: NylonFunction: waterproof, breathable, lighteningLining Material: esterSize: Length 30cm, Width 23cm, Height 46cmShoulder strap: adjustablePractical size and internal storage space- -capacity storage of books, stationery, etc. separation layout allows children to develop a good habit of storage-Selected high-density nylon fabric the characteristics of wear resistance, scratch resistance, water repellent, and dirt resistanceThe six-wheel design of climbing stairs reduces the resistance and vibration when pulling the schoolbag up the stairs, which can cause discomfort to the childrens hands when the tension is too light.