Purchased on Amazon in July. Used about 10 times and has no noticeable stains or damage. Returns are not accepted to prevent swapping. The following is a product description from Amazon: ▶【Specifications】Size is 50cm*31cm*20cm. Weight is only 1.1kg, making it easy to carry. Plenty of pockets make it easy to organize the contents of your bag. Features include a computer pocket, mobile phone pocket, and document pocket, providing excellent storage capacity! Can accommodate even a thin 17-inch laptop! Easily stores 2-3 days' worth of clothing, perfect for short trips! ▶【Unique Features】Equipped with an external USB port, allowing you to charge your phone while carrying it, making it convenient to carry. Includes an emergency whistle and compass, suitable for emergencies, disaster preparedness, outdoor activities, and camping. ▶【Breathability】The back and the underside of the straps use mesh material over cushioning material, reducing the burden on the shoulders and back while providing excellent breathability. Equipped with a chest belt for a more secure fit. The back is designed to be set up with a suitcase, making it convenient to carry and suitable for business trips and travel. Especially ideal for office workers commuting. ▶【Reinforced Stitching】The surface material uses high-density waterproof fabric that is resistant to scratches, achieving excellent abrasion resistance and durability. Uses YKK zippers, and the stitching around the zippers has been reinforced, making it even more durable than before.