HDD/SSD adapter, 3.5inch to 2.5inch

This adapter fits two 2.5inch SSDs or HDDs in one 3.5inch slot.
There are 2 variants, one with additional intakes for two 40mm fans and one without.

I think for a better air flow, some kind of rectangular exhaust makes sense if you're going to use the fan variant.

For mounting in a 3.5inch slot you need 6 or at least 4 heat inserts (M3x5 with a diameter of 4.1mm).

If your slot has only bottom holes for mounting, you can just use M3 screws or 3.5mm wood screws or similiar.