StrikerS Sound Stage X (StrikerSサウンドステージX Sutoraikāzu Saundo Sutēji Ikusu), officially StrikerS Sound stage X and commonly shortened as Sound Stage X or SSX, is a 2-CD Sound Stage whose plot takes place three years after Sound Stage of::Magical Girl Lyrical Nanoha StrikerS and focuses exclusively on the characters first introduced in the third season. As such, it is sometimes considered the fourth entry in the main Nanoha continuity. It was released on published::October 29, 2008.