The RB200 is an entire kit with everything you need to mount your Riggy-Micro to the hot-shoe of your camera (not designed for the Riggy-Assist). It inlcludes 2 RB101 cold shoe mounts which attach to the Riggy receptacles on the top and side of the Riggy-Micro. Plus, it includes a hot-shoe to 1/4-20 male for mouting the Riggy-Micro preamp to the hot-shoe of the camera.
The first photo what is included in the RB200 kit. The second photo shows the locations that the kit elements get mounted on a Riggy-Micro. The third photo shows a Riggy-Micro RM333 and the RB200 kit used to mount microphone shock mount and a wireless receiver: