Containers have enough space for somewhere between 2 and 20 items.
The following bags are converted so far:
Burlap sacks (6 slot)
the olive green backpack (8 slot),
the ALICE pack (12 slot)
olive drab green duffel bag (14 slot)
Upgraded containers can no longer be nested inside each other.
You will be encumbered by items inside containers. However, containers reduce the weight of their contents by 22% to 100% depending on their level. Bags with more items slots are more expensive to upgrade.
It is my overall goal to discourage people from carrying 200 to 400 items in nested bag after nested bag. I also, however understand that people need to carry ammunition and other basic supplies, so I will be working on this as things develop.