I wanted to mount a RTL 510 as close to the saddle as possible. The Fizik ICS mount is a ICS to CatEye and the Garmin portion is the stock RTL 510 Mount. The ICS to Garmin Varia adapter was a 3D printed part with accommodation to my 2 degree saddle down tilt.
As mounted


CatEye ICS, Adapter , RTL 510