Warlock · Affliction · tier 3 · from level 20
Fel Concentration
Fel Concentration
Rank 3/3
Gives you a 70% chance to avoid interruption caused by damage while channeling or casting your Drain Life, Drain Mana, Drain Soul, or Wrack spells.
Doesn't change the damage or healing of any Warlock spell.
Averages, counting crits and misses, for a level 60 Warlock with a typical weapon and no other gear or buffs, against a target your level. Worked out from the game's own data, the same way as the Foresight addon.