This is a really cool piece of luggage. It can be either a suitcase with attached day pack or a full-fledged backpack with detachable exterior pocket/day pack. I used this traveling in Japan and Europe and it was much easier than a roll around suitcase. Made of ballistic nylon, padded straps, handle, waist belt, and compression straps. Shoulder straps and waist belt go into zip up compartments for suitcase/airplane mode then fold out to convert to backpack mode. I believe it's between 45 and 50 liter capacity.