Conqueror's Efficiency is drop disabled. Prior to version 3.20.0, Conqueror's Efficiency could be obtained as a quest reward for completing The Wings of Vastiri.
3% reduced Mana Cost of Skills
4% increased Skill Effect Duration
4% increased Mana Reservation Efficiency of Skills
The stone may yet bleed.
A simple tool to price check your items in path of exile by "copy and paste". It is that simple!
Price in Leagues