Jabba (Just Another Better Barrel Attempt) is a storage mod that adds mass storage chests that can be upgraded to store enormous amounts of items all contained within one block. Each barrel can only hold a single type of item but it drastically reduces your storage space requirements. You can upgrade a jabba barrel to 7 tiers or 8192 full stacks of 64 items which is an incredible amount of storage for such a small block. The upgrades are costly though as they require Structural components and Storage Upgrade parts to reach the emerald level of storage.
Barrels can be upgraded to provide a variety of functions such as adding redstone, hoppers or providing additional stacks. They can also be linked together using a structural upgrade to make them work in a automated system. They can also be locked to prevent them from accepting any item or being emptied by pipes or automation. They are deep storage units compliant which makes them compatible with mods like LP and AE.
To move these barrels around they can be used with a dolly which allows you to transport any kind of chest or container that exists in Vanilla Minecraft or most other mods. The dolly can even move iron chests, BC tanks and TE or IC2 machines. This is a great way to save space in your base or house and to transport large items to other locations. The dolly has several negative effects that scale with the size of the transported object.