Hidden Effect
+10% increase to Fire Element Magic Spells
-10% decrease to Ice Element Magic Spells
-2 Avatar Perpetuation Cost for Ifrit and Fire Spirit
+2 Avatar Perpetuation Cost for Shiva and Ice Spirit
Whether you're in a full nuking setup or just bursting your Fusions/Lights, this (or the HQ) is what you should be casting Heat Breath with. Offers a large amount of accuracy, but remember it won't give you the +10% damage.
Not only Mithra and taru rangers, but in fact all rangers should seek to use this when r.acc is geared appropriately in other slots. This also opens up potential for rng/sam, so you wont be completely defenseless with the use of seigan, or pop on hasso for another 5 str (with the 4 gained from the staff)
All in all this piece has a hell of alot of ranged attack.
Use this when you summon Ifrit-MP cost -3/tic. Never use with Shiva +3MP/tic. Increases effectiveness of All fire spells by 10% while at same time decreases Ice effective spells. Unlike others have said /sam with hasso adds more than just 1 STR. It adds 5 at 37 so you get STR+9 from that setup. Oh and the Ratt+10 is a very nice perk to rng and even corsair when geared right.