The ad for the Sling Pack looked good, but so do a lot of ads. When I received my RuK, I thought I may have made a mistake as it looked small, even though that is what I was looking for. I thought there is no way my 15" laptop would fit into this pack. I was wrong. It fits like a glove and so does everything else I need. Don't let me mislead you, it's not an overnight bag, but it does carry all my essentials on a flight and fits easily under the seat. Great job RuK!