This is a simple coldshoe mounting point for cameras or cages that either lack a hotshoe or in the case that more are needed than are provided. A coldshoe is a common way to mount monitors, microphones and lots of other gear onto a video rig so having extras can always come in handy.
This mount is designed to use a standard 1/4-20 caphead or panhead screw.
This particular piece was designed because my Blackmagic Design Pocket Cinema Camera does not have a hotshoe/coldshoe. It does however have a top 1/4-20 mounting point. So rather than buying one of these off Amazon and waiting to ship I designed one up quick in Fusion 360. 3D printing is a camera rigger's dream.