The ZDX 21" Carry-On Expandable Spinner offers 2.5" of expansion depth & still fits in an overhead compartment, making the difference between having to check a bag or not…and saving time & money. Features such as an outside battery pocket so you can keep charging your phone, our Smartlink strap for connecting 2 bags & an easy-access pocket to hold items for security checkpoints are all designed to make your life on the road a lot smoother. Protected by Briggs & Riley's Simple as that® lifetime warranty.