This was designed as a request for a way to mount the new Garmin Varia Rearview Radar on a K-Edge Saddle Rail GoBig mount. It basically is a 90° Gopro adapter to my version of the Edge mount. I Modified my own Edge Mount to allow only an eight-turn to engage the device, this also provided for two orientations without the need to rotate the mount.

Garmin Varia/Edge to GoPro Adapter Mount

This should also work for Velodrome riders, since many organizations (from my faulty memory) do not allow bike computers to be mounted on handlebars during sanctioned events. It would let you mount an Edge device facing backwards from a GoPro saddle or seat post mount.