Purchased on Amazon and tested once indoors. Although it is new, please refrain from purchasing if you are overly concerned about minor details. [Details of the Rolling Boston Bag] Rolling Boston Bag: The bottom of the Boston bag has four 360-degree rotating casters. It's easy to carry heavy luggage with the casters. High-Density Oxford Cloth Fabric: It is difficult for water to enter even in sudden rain, protecting your important luggage. It is scratch-resistant and durable, so you can use it for a long time. It is the perfect size for carrying luggage for domestic travel, events, and festivals. Dual-Purpose Portable Bag: Unlike ordinary portable bags, it can also be used as a highly practical, dual-purpose, multi-functional handbag. You can carry it, roll it, and adjust the way you use it to your liking. Multi-Purpose Design: It can be attached to the handle of a suitcase, so it is stable even when placed on top of a suitcase, making it easy to move around. It has a large capacity, so it is widely used for travel, as well as for outdoor activities, disaster prevention bags, and bags for hospitalization. 3-Stage Expansion of Bag Capacity: By opening the zipper, the size can be expanded in three stages (40L/60L/85L). It also significantly saves space after folding when storing, and after expansion, it can be easily carried on airplanes and trips. Putting extra luggage in a duffel bag further improves usability. Multi-Functional Design: With a simple design, it can be used by men, women, and people of all ages. It can be used in various situations such as travel, business trips, commuting to school, overnight stays, outdoor activities, hiking, shopping, fishing, returning home, going out, sports, and disaster prevention.