Needs review
Source: Quintessential Elf 2

Description: You are particularly adept at unweaving another's magic

Prerequisites: Improved Counterspell, Words of Unbinding, 10 levels of arcane spells

So long as you maintain more than 10 levels of available arcane spells you may use any spell of greater level as a counterspell. If casting the counterspell would drop you below 10 levels of stored energy, you may not use this feat.

Normal

You may use a spell for the same school of greater level with Improved Counterspell. If you do not have Improved Counterspell you must use the same spell or a spell specifically designed to counter the target spell in a counterspell attempt.