Dark Ones Own Luck

Warlock Invocation
Level: Least, 2nd lv.
Components: V, S
Casting Time: 1 standard action
Range: Self
Duration: Instantaneous
Saving Throw: None
Spell Resistance: No

You are favored by the dark powers if you have this invocation. You gain a luck bonus equal to your Charisma bonus (if any) on Fortitude saves, Reflex saves, or Will saves (your choice each time you use this ability) period of 24 hours. You can’t apply this ability to two different save types the same time. This bonus can never exceed your class level.

(Complete Arcane, Page 133)