This is a carry-on case with an expansion function, designed with flights in mind. It's designed for in-flight travel, business trips, and vacations, and features a zipper-opening expansion structure. By expanding the width by approximately 5cm, the capacity increases by about 20%, providing peace of mind even if you acquire more luggage or souvenirs during your trip. The lightweight and durable aluminum alloy caliber can be adjusted to three levels with a one-push operation to suit your height and usage scenario. It is equipped with a wet/dry separation bag for storing wet and dry items separately. Inside, there are also convenient pockets for temporarily storing small items, smartphones, documents, tickets, etc. A dust cover with a dustproof specification is included, which can be folded and stored when not in use. Durable double-wheel casters are used, providing smooth 360-degree rotation for comfortable travel. The design suppresses vibrations and noise during travel, allowing for stable movement even on uneven surfaces. With a brake function, it's safe to use on trains and slopes. The casters are removable, making cleaning, storage, and replacement easy. The hard-type body combines ABS resin and PC (polycarbonate) resin, achieving both lightness and impact resistance. The main zipper uses a reliable YKK zipper, providing a long-lasting and stable feel. It is equipped with a TSA dial lock for peace of mind when traveling abroad. Airport inspections are possible while locked. It's a very stylish and lightweight carry-on. Perfect for a trip of about two nights! Thank you! (^ ^)