HD Mini-SAS cable configurations It is an external Mini Serial Attached SCSI HD x4 (SFF-8644) to Mini Serial Attached SCSI x4 (SFF-8088) cable The High Density (HD) system referenced as HD Mini-SAS (SFF-8644) in the SAS 2.1 standard, meets the 6Gb/s SAS specification. These new HD Connectors will be used on the SAS 3.0 specification when it is released. Cable material may change but the connectors will be the next generation of SAS to run at 12Gb/s. External HD Mini-SAS Copper Cables Length: 50cm