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
[3.14] Viper Strike Poison Pathfinder - League Start and Endgame Guide
[3.0] Yalani's Low Life Righteous Fire Build - +Eva/Armour - T15/Uber
[3.2] Necro/Scion Victario's Influence Zealot's Oath Aurabot - 11 auras 2 curses
[3.1] Support Aurabot 13 Auras Elemental DPS Boost
[3.1] Clarity_Bot's 14 Auramancer Bot (Low Expense, Strong Auras) Victario's Influence
[3.2] PartyJesus: Running ALL the Auras without Shav's