A multi-purpose bag is quite a commodity for a traveler. Most common are the trolley-type bags that can turn into a backpack like the old Eagle Creek Twist Pack 22 I reviewed before. Eagle Creek may have done something revolutionary this time with their patent-pending Eagle Creek EC Lync System. So imagine a rolling bag that has a detachable collapsible frame to convert it to a backpack or duffle bag and can also be stuffed in a smaller sac for storage. The idea seems doubtful for me at first. I was thinking, collapsible? Is it durable enough for rough handling in airport check-ins? Is it easy to assemble or convert? I had the pleasure of testing the Eagle Creek EC Lync System 22 bag more than four months now and used it for a few local and international trips already.