Double Sata ports in NAS case?

[Showbiz]

Hey guys,
Been looking at this case to build an 8 disk NAS: https://www.amazon.com/Silverstone-Technology-CS380B-Storage-Cases/dp/B01MA6NJE8

I'm sure this is an easy question, but what's with 16 sata ports for 8 drives? Searching for "double sata ports" has not been helpful. There's a good picture of the backplane further down the amazon page.

I'm planning on using SATA red drives, is the extra sata port for sas connection?

 

[Blue Fox]

Second port is for dual-port SAS drives. You can ignore them. No one is going to be using said drives in that kind of chassis anyway, so Silverstone is really just wasting money including them.

 

[Showbiz]

Thanks!

 

[Ranulfo]

All I can say is, stay away from the itx version of that case. Horrible airflow.