Standard Backpack: In order to receive this backpack, you must join the Pioneer Scouts and reach the rank of "Possum." To begin this quest chain, read the "Pioneer Scouts" poster at any Train Stations around Appalachia to begin your journey as a Scout.
Standard Small Backpack: A Plan to craft a Small Backpack can be found inside the Overseer’s Cache inside the Morgantown Airport Terminal. This Plan cannot be traded, sold, or dropped.
Small Backpacks have 50% of the carry capacity provided by a standard Backpack.