The 21 inch expandable spinner is made of Polypropylene; this is a very strong and light weight. Features include a ergonomic handle and 3 stage telescopic handle, lined 2 compartment interior – one side with a full zipper section and mesh pocket, the other with a stretchable strap, a smaller pocket for accessories and a shoe/laundry bag. Includes a built-in TSA approved lock. It has 4 double swiveling wheels, a USB port to allow you to carry your own battery; an expandable zipper, hidden name tag, top carry handle. Pairs perfectly with the BY Backpack.