Holy Symbol Expertise is an implement training feat, introduced in the Class Compendium. [Dr398:CC:Feats] Adventurers with this feat gain a +1 feat bonus to implement attack rolls made with a holy symbol, which increases to +2 and +3 at 11th level and 21st level respectively. When the adventurer attacks an enemy with an implement attack using a holy symbol, the enemies cannot gain combat advantage against the adventurer until the start of his or her next turn, unless using a power or another ability that states the adventurer gains combat advantage.