I've used this bag for business trips about 2-3 times. It's convenient for carrying clothes, a laptop, etc. It can also be expanded. I'm selling it because I'm replacing it. Size: ⭐︎Approximately 42cm x 30cm x 15cm depth ⭐︎Before expansion: Approximately 19L ⭐︎After expansion: Approximately 39L ⭐︎Large enough to hold a 17.3-inch laptop, A4-size documents and files, and 2-4 days' worth of clothing. Features: ⭐︎Can be attached to a carry-on suitcase ⭐︎Highly water-repellent and waterproof ⭐︎The front pocket uses a "water-stop zipper" *Not completely waterproof ⭐︎Multi-storage space ⭐︎Wet and dry separation pockets ⭐︎Device storage space ⭐︎Mesh material with excellent cushioning on the back contact area Weight: Approximately 1.27kg