This is adapter for tacx tablet holder mounted on handlebars for indoor bicycle trainers.
https://www.garmin.com/en-US/p/690898
Since aero bars are flat 52x27mm in size, the original tacx holder can't be mounted on them, this model contains replacement parts to mount holder.
this model is locked at 45 degrees and is not adjustable.
for assembly original tacx m5 screw and knob can be used.
for mounting on handlebars 4x m4 screws and nuts are required.
The author hasn't provided the model origin yet.