Internal Mini SAS SFF-8087 to mini sas High Density HD SFF-8643 data Server hard disk raid Cable 50cm
[SF-070]

These are specialty cables, not something the average consumer will have a use for, so they're pretty pricey, but this isn't something you can work around or live without. The quality is very good though - the connectors are solid and strongly connected to the cable, and the cable itself has plenty of heft. Works, and should hold up over time.