I figured if anyone could find the answer was everyone here.
I need to increase my FreeNAS storage and I’m looking at the HGST HE8 8TB 7.2k SAS 12GB/s 3.5" HUH728080AL4200 drives i found on ebay for a great price. I have a NetApp DS4246 Disk Shelf hooked up and running great but that is SAS 6GB/s unit.
In the comments of this ebay post they say that the unit must support 4kn HHD. Before i drop the money on these drives i just want to make sure that these would work in that disk shelf.