The Level 1 Backpacks are simple storage mod that will allow you to carry a small amount of items, which in turn increases your overall inventory
The Level 2 Backpacks are a storage mod that will allow for a medium haul of item storage which in turn increases your overall inventory.
The Level 3 Backpacks are a storage mod that will allow for a large haul of item storage which in turn increases your overall inventory by +250.
Utility Belts are belts increase the amount of inventory spaces.