The primary difference is in size and capacity. The 20u0022 Carry On is designed to meet domestic carry-on size restrictions and is ideal for travelers who want to pack light. In contrast, the larger models, such as the 24u0022 Medium Spinner and 28u0022 Large Spinner, offer more packing space and are suitable for longer trips or those who prefer larger luggage. Also, be aware that TSA-approved keyless combination lock comes only on medium and large spinner.