The backplane is made to be integrated in my DIY NAS server case, behind the HDD cage.
Each backplane is design for 3 HDDs powered by 2 SATA power connectors and you need 2 of them for my DIY case.
Power and data connectors are on one side and SATA headers on the other.
Here is the result :
I love this. Question though how hard would it be to increase this to a 5 disk?