Each episode of the season attracted more than a million viewers on its first airing. Between January 31, 2006 and September 19, 2006, five DVD sets were released in the United States, each containing four episodes from the season. On September 12, 2006, Nickelodeon also released the "Complete Book 1 Collection Box Set", which contained all of the episodes in the season as well as a special features disc.[4] The original releases were encoded in Region 1, a DVD type that plays only in North American DVD players.