Q:I know that the answer to the question "What happened to 16 2/3 rpm speed at last?" is in "Some recordings, such as books for the blind, were pressed at 16 2⁄3 rpm. Prestige Records released jazz records in this format in the late 1950s; for example, two of their Miles Davis albums were paired together in this format. Peter Goldmark, the man who developed the 33 1⁄3 rpm record, developed the Highway Hi-Fi 16 2⁄3 rpm record to be played in Chrysler automobiles, but poor performance of the system and weak implementation by Chrysler and Columbia led to the demise of the 16 2⁄3 rpm records. Subsequently, the 16 2⁄3 rpm speed was used for narrated publications for the blind and visually impaired, and were never widely commercially available, although it was common to see new turntable models with a 16 rpm speed setting produced as late as the 1970s.". Can you tell me what it is?
A:
never widely commercially available