The term 'knapsack features' refers to the straps that are used to secure a knapsack or backpack. These straps are typically adjustable and are designed to provide comfort and stability when carrying a heavy load. The straps are usually made from durable materials such as nylon or leather, and they can be adjusted to fit different body sizes. Knapsack features also include pockets, compartments, and other features that make it easier to organize and store items in the bag.