The Microsemi Adaptec ACK-I-rA-HDmSAS-mSAS-.8M is an internal &quot;right angle&quot; Mini Serial Attached SCSI HD x4 (SFF-8643) to Mini Serial Attached SCSI x4 (SFF-8087) cable. It measures 0.8 meters and is used for connecting a SAS/SATA adapter to a SAS/SATA backplane.