Diamond Soul
From Neversummer 4 Wiki
Type of Feat: Class
Prerequisite: Monk 12
Required for: None
Specifics: The character gains Spell Resistance equal to their level + 10.
Use: Automatic
This feat means monks will not need to wear items with spell resistance as they do not stack.
The level mentioned in the description is the Monk level, not the character level (so a multiclassed character with 12 Monk levels and 4 Fighter levels only has 22 SR, not 26)