In this Airsoft Manuals episode of Taiwan Gun, they show the ways the 8Fields Multi-purpose Expandable Backpack can be configured... "A multi-purpose expandable backpack in which, with the help of a zipper, we can increase the capacity of the main compartment from 12L to 24L. In the main compartment, there is a laptop compartment or a hydration bag that can be mounted with 2 hooks.