As the description says, you can cube it to get some items.
It always gives the same predefined unique item classes depending on your Character Class. It might give you something other than what's listed below but the chances of it are very low.
Items can be Tier 1 or 2.
Hover over an underdotted word to see Full list of what items are included in that item type.
NOTE: These Uniques cannot be disenchanted, but can be disenchanted normally after uptiering them.