You wouldn't take a front-wheel-drive car four-wheeling in the mountains; you'd take your souped-up rock crawler. The same logic applies to your luggage, and when you don't want some flimsy everyday luggage holding your travel essentials, you should carry the Eagle Creek Tarmac AWD 22 Carry-On Bag instead. At 14x22x9in, the Tarmac AWD 22 falls within size restrictions for most major airlines carry-on luggage. Triple-ply polycarbonate back shell fabric resists elephantine abrasions, whether it's from ragged concrete curbs, worn-out overhead compartments, or rugged dirt roads. The front fabric consists of rugged Bi-Tech, designed to put up a strong front in the face of (literally and figuratively) rough situations. Dynamic Spin Wheels, encased in sturdy wheel housing and protected by bumpers, twist and wiggle 360-degrees for easy handling over any terrain, be it cobblestone streets, gravel driveways, or potholes bigger than Delaware.