The RS 6661A-mSAS3 is a portable, high-performance Hardware RAID solution for Thunderbolt™ 3 capable platforms. 
 
RS6661A-mSAS3 key features:
Thunderbolt™ 3 to 2x Mini-SAS Ports (SFF-8088)
Portable, High-Performance Hardware RAID solution for Thunderbolt™ 3 Connectivity
Integrated H/W RAID 0, 1, 5, 6, 10, 50 & JBOD Support
Directly supports up to 8x 6Gb/s SAS or SATA drives and up to 112TB of Storage Capacity
Works with any Thunderbolt™ 3 capable Mac or PC