A flywheel adapter for a 04B30T sprocket with a 30mm hub. Will fit a 83mm Flywheel.
Get the "outer rim" here:
https://sketchfab.com/3d-models/04b30t-sprocket-flywheel-adapter-outer-ring-45fbacd5084d4eccb8e4bd784c161cf0
You´ll also need 6x 60mm M4 screws.