Productions and Prentice Hall Media (formerly Warren Schloat Productions). Home entertainment In the early 1950s production companies started producing filmstrips for home entertainment. There were a number of filmstrips from Disney and the Society for Visual Education Inc.(Chicago), among other. Eastern Europe production Film strips were popular in the USSR because movie projectors and VCRs were not in common use until the early 1990s. A great number of films were produced by the "Diafilm" studio. Many filmstrips were produced by "cinematographic studios" in former Soviet bloc countries such as Poland and Hungary during the 1950s and 1960s. In Greece they were known and sold by the name "tainies Argo Film" (Argo Film movies) from the name of the company (Argo Film) that translated the scripts into Greek and organized the productions' distribution in Greece. The titles included children's stories, fairy tales, Greek history, Christianity, adventure, science fiction and war stories. Automatic film advance During the 1970s, projectors became available with built-in phonographs or cassette players that could automatically advance the film by means of a 50 Hz subaudible tone recorded on the accompanying record or cassette, which would signal the projector to advance the frame. Most cassettes accompanying filmstrips in the 1970s and 1980s would have the same audio material on both sides of the tape. One side would have audible tones for the fully manual projectors, and the other side would have the subaudible tones for automatic projectors, while some had both audible and subaudible tones combined. In 1979–1980 the DuKane Corporation in St. Charles, Illinois began to produce a cassette automatic filmstrip projector called the DuKane Micromatic II. The La Belle Commpak system used a 1000 Hz tone on 8-track tape to advance to the next slide. The General Electric Show'N Tell record system used 16mm for film, and record for audio (though the Show'N Tell would advance the film at a fixed rate through a gear). Decline and obsolescence The 1980s brought the advent of the video cassette recorder (VCR), which became increasingly affordable. When VCRs became within reach for most schools' budgets, filmstrip use declined. Videotape instruction combined the ease of the filmstrip with automatically synchronized audio and full motion video. By the early 1990s, the vast majority of filmstrip producers that were not equipped to compete with video either closed or sold their businesses. In the late 1990s to early 2000s, some audiovisual companies (such