The USB-Infinita Universal Rolling Platform is perfect for the frequent flyer traveler. It fits USB, USB Plus Black Label, and Infinita carriers. It is removable, so you can use it when you need it. Move effortlessly through busy airports with the remarkably smooth and controlled handling experience of the follow-me TPR castors solution, with two inline rear wheels and two front swivel wheels (both with double bearings). Includes a comfortable nylon leash pull with EVA handle