A backpack—also called knapsack, rucksack, rucksac, pack, sackpack, booksack, bookbag or backsack—is, in its simplest frameless form, a cloth sack carried on one's back and secured with two straps that go over the shoulders, but it can have an external frame, internal frame, and there are bodypacks

If you’re just thinking about getting into backpacks, chances are you are overwhelmed with the choices. And if you don’t know anything about backpacks, it can be really hard to choose the right one for your needs.