The square shape made whole bag more stylish ; big opening pocket is convenient to put 15 inch laptop, A4 papers,or clothes; the rubber trim with metal buckle in the middle; with two deep pockets in the front can put some personal belongings,such as powerback, earphones,tissues,keys,and so on.; the side pockets can put bottle and umbrella; on the back panel ,there is a invisible pocket,which can keep some cashes or cards.