the Adaptec Ack-i-hdmsas-4sata-sb-.8m Is An Internal Mini Serial Attached Scsi Hd X4 (sff-8643) To (4) X1 Serial Ata (adapter Based) Fan-out Cable With Sideband Signals (sff-8448). It Measures 0.8 Meters And Is Used For Connecting A Sas/sata Adapter To Sata Disks, Or A Sas/sata Backplane.