The PSR-300 Yamaha is a digital keyboard, featuring first-generation AWM (Advanced Wave Memory) waveform ROM.
Notable characteristics of this accompaniment keyboard include 100 AWM voices, a polyphony of 28 notes, 50 auto-accompaniment styles, touch response, MIDI, stereo speakers etc
Other nice features include split and fingered mode for the left hand, separate controls for accompaniment volume, transpose, and tempo, and a dedicated button for setting the split point.
You can also layer two voices using the "Dual Voice" on-off button (great for improving/fattening the base sounds).
Then there is the "sustain" button I was talking about earlier, and a "Harmony" control (adds harmonized parts to the right hands) - you can pick between Duet, Trio, Block, Country and Octave harmonized parts, very handy, especially with the jazz styles.