A 256k Fluid Storage Disk is an item where items from the storage system are stored on. It has to be put in a Disk Drive.

The 256k Fluid Storage Disk won’t despawn when dropped in the world.

Uncrafting

Sneak and right click while holding the empty 256k Fluid Storage Disk to retrieve the various parts back:

Storage capacity

The 256k Fluid Storage Disk can store 256.000 millibuckets or 256 buckets of any fluid.