The optimum use of a disc record of constant rotational speed occurs when the innermost recorded diameter is half of the outermost recorded diameter. But why worry yourself with the details. The Crosley Portable Suitcase Style Turntable plays all three speeds, 33 1/3, 45 and 75 RPM records. By the late fifties, stereo records reached a peak in the marketplace as hi-fi sound reproduction attained its largest audience to date. The portable turntable was introduced in the late 1950's and provided music lovers with a sense of independence, allowing them to easily cart their record player from one locale to another. The popularity of this unit was due in no small part to its portability, but also to its suitcase-styled finishing touches that became a Crosley hallmark. So whether you choose Ella Fitzgerald or Elvis, celebrate your vinyl in portable style.