Unique Flask - Insane Price Variations

Had a few Players now asking about this Flask though its not up for Sale. Must be the Vaal-Damage Mod. Saw also some very insane Prices for this Flask. So i cant really figure out how much this is actually worth. Maybe some of you can shed some Light on this.

i would asume it goes for an 600ex to a mirror for the right one

with 40% soul gain prevention starts 30ex but only with 101% increased dmg

39% soul and 110% dmg ramps up to 100ex

and

32% soul and 120% dmg ramps up to 1 mirror

i think yours is the best on market atm.