Some items may be stamped with the term Set of …. These items, likely powerful on their own, can become even more so if multiple pieces of the same set are equipped.
Sets are quite rare. They are often found on armor, but not exclusively. Indeed, items belonging to a “set” are available on all types of items: weapons, armor, tools, jewelry, etc.
Each set indicates the required amount to unlock the stated stats. See the example below.
As you can see, the set in question is named “Set of Solis”. To obtain the stated stats, you will need to be equipped with as many pieces bearing the same set notation as indicated in brackets ([X]).
You might think that items with a set are below average, but once fully equipped, they can offer significant advantages!