This part is a remix from this rial bracket: https://www.thingiverse.com/thing:4435764 

I put the clamp in to a box, added Thread Inserts and a strain relief. 

Printing:

• PETG (for no special reason)
• 0.2 mm
• no supports

Parts using Inserts:

• Shelly RGBW2
• Threaded Inserts M3x5,7 
• 6 M3x8 screws

Parts using wood screws:

• Shelly RGBW2
• 6 3.5 x 10 wood screws with flat head

Please note that the pillars from the m3f files are modifiers for the infill and not solid objects.