Mint condition rucksack No 21. The Fjällräven Rucksack 21 20L backpack has a large main compartment that is accessed from the top. There's a padded pocket inside to store a laptop, tablet or any electronic device with a screen size up to 15 inches. There is also a removable pad which provides extra comfort and a special pocket that keeps a flask or bottle upright. The backpack's top cover stays in place via straps that stick to the bumps on the front. The exterior has an open pocket and two pockets on the sides.