Question, sorry if it gets asked a lot.

[Monkay]

Hello, everyone, another question;
I have started a new High-Elf Ranger and on Dlvl5 I found a Black Dragon Scale Mail (-2) [16,+10]
I never have obtained Dragon Armour before and this one gives me rAcid and lets me breath acid balls that do 125 damage. Just wondering if this is counted as a artifact or a ego item, what is the rarity of finding this and what is the value/usefulness of it.
I always found it hard for rangers to deal heavy damage early on, and this is helping me a lot. I just blast uniques and packs of monsters, run, and then do the same again and again, so far it works great.