A container for liquids that can (by default) hold up to 32 buckets. It's possible to restrict the type of liquids by placing a bucket with the specific liquid in the filter slot
Using
Right-click with buckets or other fluid containers to fill or drain the tank. Pipes can also interact with its fluid capability.
Filter
Put a filled bucket in the filter slot to lock the tank to that fluid. Remove the filter item to allow any fluid again.