Mage · Fire · tier 1 · from level 10

Improved Fire Blast

Rank 2/2

Reduces the cooldown of your Fire Blast spell by 2 sec and increases its range by 15 yards.

Doesn't change the damage or healing of any Mage spell.

Averages, counting crits and misses, for a level 60 Mage 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.