This is a Pioneer PD-S501, a hi-fi CD player known for its unique mechanism. Key features Stable Platter Mechanism: This is a striking feature whereby the CD is placed upside down on a kind of turntable platter for more stable rotation and better sound quality. Pulseflow DAC: The device uses Pioneer's own 1-bit “Pulseflow” digital-to-analog converter. Controls: The player has a 10-key numeric keypad on the front panel and an adjustable headphone output. Additional specifications In addition to the weight, these are the other physical and technical characteristics of this model: Dimensions: 420 x 110 x 276 mm (Width x Height x Depth). Years of production: Built between 1992 and 1993 in Japan. The device is equipped with a solid base plate and a stable front plate, which contributes to the robustness of the well-known “Stable Platter” mechanism.