The Microsemi Adaptec ACK-I-rA-HDmSAS-HDmSAS-1M is an internal "right angle" Mini Serial Attached SCSI HD x4 (SFF-8643) Mini Serial Attached SCSI HD(SFF-8643) cable. It measures 1 meter and is used for connecting a SAS/SATA adapter to a SAS/SATA backplane.