This is a demo of the Muson Synthesizer, a rare mini organ with a built-in sequencer, created in 1978 by Mego Corp.
About the Muson Synthesizer, miniorgan.com says:
Kind of a ROLAND TB-303 but much cooler & cheaper – still cheaper… The coloured buttons can be used to change the melody and rhythm. Each color has a different tune. You can also change the speed and pitch of the sequence with 2 sliders. This was also released by Palitoy in the UK.
“Kind of a Roland TB-303” is a bit of a stretch – but it’s certainly a unique vintage music toy.
The keys play just over an octave of whole notes. The colored pegs above the keys operate the built-in sequencer. Each color represents a note on the keyboard.