Backpack

Generally, 3D Backpacks fall into one of four categories: frameless, external frame, internal frame, and bodypack. A pack frame, when present, serves to support the 3D Backpack and distribute the weight of its contents across the 3D body more easily, so most of the weight does not rest on the shoulders, restricting range of motion and possibly causing damage from pressure on the straps. Most 3d Backpacks are capable of being closed with either a buckle mechanism, a 3D zipper, or a dry-bag type 3D closure though a few models use a drawstring fitted with a cord lock for the main compartment.