【Large capacity × expansion function】 Approx. 42cm× Approx. 30cm× Depth Approx. 15cm (before expansion: approx. 19L) (After expansion: approx. 39L) A 17.3-inch laptop, A4 size documents and files, and 2~4 days' worth of clothing, making it a convenient business backpack for business trips and travel. It can be fixed to the carry case, so it is easy to move. [Highly water-repellent treatment × waterproof function for sudden rain] It is made of highly water-repellent leather material, making it difficult for water to pass through the business bag and maintaining waterproof performance for a long time. In addition, the front pocket adopts a "water-proof zipper" to effectively stop rainwater from entering. (*Not completely waterproof.) ） [Multi storage] Space for frequently used items. It can store plenty of A4 size files. [Trunk storage] It has a wet and dry sorting pocket, and can store 2-4 days' worth of clothes and wet items separately, making it useful for business trips and travel. [Device storage] The perfect space for a computer or documents. It can easily store a 17-inch PC and is easy to take out from both vertical and horizontal positions. [Anti-theft pocket] On the back, there is a pocket that makes it easy to put in and take out valuables such as mobile phones and wallets that you use every day. [Attention to detail] Multifunctional business backpack with a large capacity of 39 liters / 4 security functions / 2 WAY / water repellent / water-proof zipper / use / 17-inch PC compatible / expansion function / multiple storage / no need for a suitcase when traveling / with back security pocket / easy to put in and take out of Suica and other pockets / etc. [Backpack that is not easy to get tired of cushioning] The breathable and cushioned mesh material absorbs sweat, preventing uncomfortable stuffiness and shoulder misalignment. It also reduces the burden on the shoulders and back, making it less tiring and more comfortable. [Material] Outside: (Oxford) Inside: Polyester [Weight] Approx. 1.27kg