The Zdx 21" Carry-On Expandable Spinner offers 2.5" of expansion depth and still fits in an overhead compartment, making the difference between having to check a bag or not…and saving time and money. Features such as an outside battery pocket so you can keep charging your phone, our Smartlink strap for connecting two bags and an easy-access pocket to hold items for security checkpoints are all designed to make your life on the road a lot smoother.