Binoculars, much like telescopes, are an instrument used to view objects from a great distance. Unlike telescopes, however, both eyes can be used.
In 1986, Edna Strickland used binoculars to spy on people in the Courthouse Square, whom she believed to be causing trouble. When visiting to return a shoe to her, Marty was allowed to use them and looked at the Valley Video, discovering that the building was first built in 1932.
By 2015, a new type of binoculars, called a binocular card, was invented. These were the same shape and size as a credit card, and could also take pictures. During October 21, Doc used a binocular card to keep watch of Marty McFly Jr..