Use 2 or 3 of these to hold the Korg Wavestate synth in place.  I used them on a wooden drawer that I build into my desk.  You'll need to measure the slots under the wavestate and position these blocks appropriately.  Use 2x woodscrews to fix to the wooden surface, or glue/tape them.  Material is pretty much anything and layer height is not relevant as you cannot see the items when in use.

These will probably work for some other Korg synths as well.