Kinefinity Eagle e-Viewfinder Rosette Plate

A rosette is the toothed interface that lets a viewfinder be set to an angle and then locked there, rather than relying on a clamp holding by friction. This is the rosette plate for the Eagle HDMI e-Viewfinder, and it is what the finder hangs on.

Two thread options exist because rigs do: the 1/4 inch-20 version fits the imperial hardware on most cages and arms, the M6 version fits the metric mounting points on other builds. They are otherwise the same part, so buy by the thread on the arm you already own.