Non-Class Skills (oskills)

An oskill is a skill an item lets any class use. The tooltip names the skill without a class tag, e.g. "+12-18 to Inferno" on Flamebellow, and every character wearing the item can cast it at the level it rolled.

How it adds up depends on whether the skill is in your own class's tree:

• Another class's skill: you get exactly the level on the item. All Skills and Class Skill Levels do not raise it, and its synergies give nothing, because you cannot put points into them.
• Your own class's skill: the oskill levels add to your points and to every other +skill, just like Single Skill Levels.

An oskill from another class gains nothing from +all skills: the level on the item is the level you cast.

Frostwind (Arctic Blast) and Widowmaker (Guided Arrow) are other examples. The Skills page lists every skill by class.