This is a giant duffel bag that is specifically designed to put your backpack in while flying. It protects your backpack from getting damaged to a cretin extent, and is very durable. This way, your big backpacking back pack will not get any of its straps or pads stuck or ripped off while luggage carriers or conveyor belts move it. It is large enough to fit most backpacks (It has room to spare when my 85 liter backpack is in it and maxed out) and very durable. It is also covered by Ospreys lifetime guarantee!
The only problem I have with it is that it only has one shoulder strap that can be used to haul it around. This makes it hard to carry or move it through airports. It's has you carrying your backpack with all its gear and supplies in it with only one strap. Hopefully newer models will have more options when it comes to hauling methods. As for now, I just carry it around the airport until its time to part with my pack. Then I just slide it in its big bag and off it safely goes.
When you’re not using it, it folds up into itself using a little Velcro pocket, which makes it very compact and handy.
Features* Two-way zippered opening at the end of this pack duffel for easy loading and unloading of your backpack
* I.D. window pocket on front for easy identification
* When not using stash it inside the built-in pocket for easy storage
* Lockable zippers; locks sold separately
* Volume is 8,225 cubic inches
Approximate volume- 8,200 cubic inches
Average weight- 13 ounces