A box set entitled "The Hitchhiker's Guide to the Galaxy: The Complete Radio Series" was released on 3 October 2005. It contains fifteen CDs, subdivided per radio series, and bonus material exclusive to the box set. BBC Audio released a DVD version of the "Tertiary Phase", featuring that series in 5.1 surround sound, in October 2006. Contrary to previous announcements, this was merely a DVD-Video disc with Dolby Digital sound and other features, rather than a DVD-Audio disc. While it had been stated that BBC Audio plans on also releasing the fourth and fifth radio series on DVD, no dates have been set.