A special version of Topodesigns Klettersack with leather bottom and the lower sides. Very handy for placing the backpack on wet or rough ground. It keeps the rucksack dry and protects the Cordura (Not that 1000 Cordura needs too much protection, it´s already a tough material). The name Klettersack is earned by its functionality and solid construction. The weak spot of a Backpack is always the Zippers. As you can see Topo uses big and tough YKK ones. The lifetime of a Zipper defines the lifetime of your bag. They are hard to replace and if possible, it gets expensive. Avoid a backpack by all means with to small ones or those fancy watertight ones (they are crap).
The size of the backpack with 22 litres is just perfect for your daily use, a day in the mountains or other outdoor activities. With the straps and the additional ones available you will be able to increase the capacity to your needs. I got a serious faible for backpacks and I guess sooner or later my collection will be expanded by a Topo one. (and one with a broken/faulty zipper will get retired).