Strong zippers, strong and flexible material. Silent and large double wheels. Carrying handles both on the side and on top. Approved TSA lock. The KKDK Flex suitcases are made in a set of 3 sizes. The cabin suitcase is good for 2-3 day trips. The medium suitcase is good for 7-8 days and the large size is approved as check-in for approx. 2 week trip.