Epic Spell Penetration
From Neversummer 4 Wiki
Type of Feat: (Epic) Metamagic
Prerequisite: 21st level, Greater Spell Penetration
Required for: None
Specifics: The character gains a +6 bonus on caster level checks to beat a creature’s Spell Resistance.
Use: Automatic
Does not stack with Greater Spell Penetration despite both feats appearing on the character's list of feats