I learned the hard way that the foam pad included with the Fjällräven Kånken backpack is not packing material, but is a combination seat pad and “shape-holder.” After having tossed a couple of those pads and learning that the local Fjällräven shop (a) gets a lot of inquiries from folks like myself who chuck those pads and (b) does not stock replacement pads, I ordered this foam sheet roll and crafted replacements for our Kånken backpacks.
The foam sheet is a bit thicker than the OEM pads, so a bit of creative trimming is required, but it’s a small price to pay for a lesson learned!