The R2 swivel adaptor allows you to use your CineMilled Readyrig “Swivel” and mount it directly to the top of the DJI Carbon ring that comes with your R2 kit.
If you already own a Cinemilled PRO Ring this can allow your to have the swivel setup on the DJI ring so you can quickly switch back a forth from Pro ring and spindles to DJI ring and swivel!