"21:9" ("twenty-one by nine") is a consumer electronics (CE) marketing term to describe the ultrawide aspect ratio of 64:27 (2.370:1 or 21.33:9), designed to show films recorded in CinemaScope and equivalent modern anamorphic formats. The main benefit of this screen aspect ratio, compared to the more common 16:9, is the absence of the black bars at the top and bottom of the screen when viewing content in this format, and a constant display height when displaying other content with a lesser aspect ratio. SDTV HDTV "21:9"