This cable (stamped 590-0878 or 590-0837) is used to connect the hard drive and CD drive inside various Macintosh II systems and the PowerMac 7100. It can also be used in the Mac Classic or Mac SE (one connector would be unused in these systems).
Of course it can also be used in PC or UNIX systems with devices using the same 50-pin SCSI connection.
The cable is in great condition with no signs of damage.
