Seasons one through nine have been released on DVD in Region 1 and 2, while only seasons one through eight have been released in Region 4. Seasons five and six were also released in the now obsolete HD DVD format on November 28, 2006, and September 18, 2007, respectively. Seasons six, seven, eight, and nine have also been released on Blu-ray formats. The DVD releases include commentary by cast and crew members on selected episodes, deleted scenes, and behind-the-scenes featurettes. The promotional tie-ins, Chloe Chronicles and Vengeance Chronicles, accompanied the season two, three, and five box sets respectively. Other special features include interactive functionality such as a tour of Smallville, a comic book, and DVD-ROM material.