what does this フェリル/レインボウ unit mean?

[evange]

It adds nothing but have a special effect saying 属性防御補正5%.
So it adds 5% of your total defense? and is it stackable?

[Angry_Ryudo]

Feril / Rainbow

+5% elemental defense. Useless if your armor is non-elemental.

[evange]

Feril / Rainbow

+5% elemental defense. Useless if your armor is non-elemental.

thnks >.<