Fly frequently and the lesson becomes obvious: check bags at your own peril. TheCarry-On Zip was designed with spatially frugal travelers in mind, but don't let its carry on-legal size fool you. This bag can swallow a mountain of gear, clothing and if unavoidable business-casual attire. Most impressive is the levelof protection that the Carry-On Zip offers, thanks to RF-welded seams, fully waterproof YKK zipper and tough, 19-oz. scrim-reinforced vinyl material.