I saw this kankan size guide while looking up Oslo Fjallraven store pics on Google. It's my dream to go to Oslo one day. I think the chart is great for comparing
Fjallraven Kanken Backpack Size Guide & Clothing Chart | My Fox Bag
Fjällräven size guide | Varuste.net English
Fjallraven Kanken Backpack Size Guide & Clothing Chart | My Fox Bag
Size Guide - Fjällräven Functional and durable outdoor equipment