Not available from Sybian themselves (and it should be) but glad someone thought of producing this, as it definitely helps bring direct clitoral stimulation to the rider, without them having to lean so far forward to be simultaneously stimulated, while enjoying the insertion properties of the Sybian or Motorbunny accessory. The rider can remain fairly vertical while straddling the machine, and yet still get direct clitoral contact; the "larger" riser does the best job of achieving this. IF you have an attachment with a stimulator such as a rabbit-style assistant, the riser MAY be too much; the riser makes the best experience when there's simply nubs or ridges provided for clitoral stimulation.
My Lady really appreciated the "help" of these risers!

I found the original "red risers" were very effective but for some reason discontinued. Sybian issued a strange leather pouch-like riser but it doesn't seem to be as effective as the Motorbunny risers. Definitely worth the money for the extra bump your girl may need.

Just when you need a little more ride.