2.39:1 Aspect Ratio

"...2.39:1 – A.k.a. Cinemascope (“Scope” for short) or widescreen (in the film industry), this is the other standard ratio for cinema projection. It is achieved either by cropping a 16:9 frame or by using anamorphic lenses to squeeze the image horizontally. Note that many cameras offer 2.35:1 framing guides rather than 2.39:1, but the difference is negligible, and these two designations are used pretty much interchangeably, as well as 2.40:1. On TV, VOD and so on, 2.39:1 movies are generally letterboxed to fit the ratio onto the 16:9 screen..." (neiloseman.com/aspect-ratio/)