The black knob for the Korg SQ-1 is bigger than the original knobs. Due to the increased size and improved profile, it provides a better handling than the small original knobs.
The center of the knobs is hollow which allows the red light of the step sequencer to shine through.
For the Korg SQ-1, 18 buttons are required. They can be printed with PLA without any support material. To print the round mark on top of the button, pause the print and change the filament.