This is an IKEA Skadis mount for the Brennenstuhl Premium extension leads.
Should work with any of these Premium-Line models:
Suggested print settings:
To attach it to the multiple socket, one of the sides must be unscrewed. The holders can then be inserted.
If you are looking for the DUO (double row mount) check this model:
IKEA Skadis mount for double row Brennenstuhl Premium extension lead
Update 2024-10-17:
The author remixed this model.
Based on the orginial layout I created a small mount for the IKEA Skadis.