Casio SA-81 Portable Keyboard

More than just a toy, the SA-81 mini keyboard comes with a new sound source and 8-note polyphony.  It includes 100 tones, 50 rhythms and features a simple change-over switch between the piano and organ sound.  The SA-81 features a cool retro design.
 
Layer: Play two tones layered together
Sustain: Allows the sound to play on (sustain) after the key has been released.
Reverb: Adds a reverberation effect to the sound for a broader range of musical expression. Choose from four types: ROOM, HALL 1, HALL 2 and STADIUM.
Octave shift: Raise or lower the pitch of notes in octaves to cover a wide range of registers
Scale Tuning (Temperament): In addition to the standard Equal Temperament tuning, choose from 16 other types of scale tuning, including Pure Major and Pure Minor tunings ideal for vocal harmony practice.
Tuning: Adjust the tuning in 0.1Hz increments to match other instruments or vocals
Transpose: Raise or lower notes in semitone steps
Metronome: Useful for practicing playing at a constant tempo
Tempo adjustment: Change the tempo of the rhythm and metronome to suit the music
Maximum 32-note polyphony: Designed so that keys will sound even when many others are played at the same time
LCD display: Full-dot, three-level LCD display for an at-a-glance view of operation/function settings
 
https://youtu.be/Bi3-Ik5Qozw