The RR 2722A is an external eight-channel, 6Gb/s, SAS/SATA, PCIe 2.0 x8, RAID controller.
 
RR2722A Key Features
PCIe 2.0 x8 Host Interface
2x SFF-8088 External Mini-SAS Ports
Directly Supports up to 8 HDD/SSD and up to 112TB of storage
Supports 0, 1, 5, 6, 10, 50 and JBOD / non-RAID Mode
(Note: RAID 6 not supported for macOS)
Supports OCE (online capacity expansion) and ORLM (Online RAID Level Migration) - not supported by macOS
Supports Windows, macOS, Linux and FreeBSD platforms
Comprehensive RAID & Storage Management Interface