This is an internal Slim-SAS cable designed for the Dell PowerEdge R750 24 bay server. It’s a short run of cable to connect a front RAID/HBA controller to the backplane.
One end of the cable is labeled FCTRL_B. This end plugs into your RAID or HBA controller.
The other end is labeled EXP_DST_SB1 (Expander Destination Sideband 1) and plugs into the backplane.