Ski backpacks. Up to 40 liters. The same trick as with assault backpacks: there are a lot of bells and whistles for snow equipment, bindings for skis, snowboards, etc. Some even have a built-in avalanche system. On a hike, all this will not be useful, but such backpacks will withstand long transitions - so in extreme cases you can take one with you. The main thing is not to buy one especially for a hike, so that later you will not be surprised why nothing fits into it.

Children's backpacks. Up to 50 liters. Children's backpacks are certainly very different from each other, since children are different, compare a six year old with a fourteen year old. The gear industry, by the way, is trying to accommodate all ages and provide unique gear for every period of life, so this is clearly suitable for your children. But for you - no. The backpacks take into account the peculiarities of the child's body, and using such an adult is like a child using an “adult” backpack. Be vigilant, these backpacks are similar to trekking or assault backpacks, but usually located in a different department. And the seller, if anything, will explain to you that such a backpack is not for you. https://mysticmountainnaturals.com/how-to-pick-a-nice-beach-bag/

Tactical backpacks. 15-100 liters. Designed for the military - that is, with them, you can travel long distances without problems. A peculiarity of backpacks: khaki color, you can easily distinguish them from tourist ones, which should be visible from afar. Tactical backpacks have a couple of nuances. The most important: the vast majority of tactical backpacks are horrendous Chinese production, and they crawl with a bang. The owner of this has to constantly hem, and the design of such backpacks does not make life easier for the carrier. And good tactical backpacks are even more expensive than tourist ones. So, since you've decided to go hiking, buy a travel backpack with bowls and wallet compartments instead of a tactical backpack with compartments for bullets and binoculars?