The Ronin Dovetail Plate for RED, Canon, Blackmagic, and Nikon from DJI is a sliding plate required when mounting certain cameras to the gimbal. It works with select cinema cameras from RED and Blackmagic Design, as well as DLSRs from Canon and Nikon, and finally the cinema camera line from Canon. It has multiple points of attachment for easier balancing.
Note: This is for the standard Ronin only. It is not compatible with the Ronin-M.