1.[Vacuum Compression Bag] There is a vacuum compression bag inside the largest compartment of the backpack, you can put the clothes into the vacuum bag, tighten the zipper, open the one-way exhaust valve, through the squeeze or air pump (need to buy their own) for compression, to reduce the items take up the volume, load more things. Please note that the zipper used in the vacuum bag requires more force to pull, this is to ensure that the vacuum airtight, not zipper damage is not smooth. 2.[ Multifunctional Backpack] The Travel work backpack size is 453016CM/17.7211.816.3inch (Manual measurement may have error, no more than 3cm). The main pocket can hold 2-3 days of clothes. The front compartment with various pockets can be used to store notebooks, pens, headphones and other small items for quick picking. This travel bag has a laptop compartment that fits most 15.6 inch laptops. 3.[USB Charging Port Design]The travel backpack features a USB port, allowing you to conveniently charge your electronic devices by connecting them to your own power bank, enabling you to easily charge your phone while on the go. 4.[Bottom Shoe Compartment and Wet/Dry Separation Compartment]The backpack features a bottom compartment for shoes to keep them separate from other items and clean. There are two ventilation holes on the shoe box to keep it breathable and prevent odors. The front pocket of the flight-approved travel backpack is made of high-density material and helps you separate dry items from wet clothes or towels. 5.[Luggage Strap & Anti-Theft Pocket]The back of the casual travel backpack is equipped with a strap that can easily be slid over the extendable handle of a suitcase. This way, you can place the backpack on top of the suitcase and make your travel easier and more comfortable. There is a pocket on the back of the backpack with anti-theft security.