Sans Digital MobileSTOR MS2UTN+ 2 Bay SATA to eSATA/USB 2.0 RAID 0/1/SAFE33/50 Enclosure (Silver) Hardware RAID engine, supporting RAID 0, RAID 1, Spanning, JBOD, SAFE33, and SAFE50. GUI mode allow customized RAID mode setup. Up to 2 RAID volume with different RAID mode can be set. Drive interface: 2 x 3.5" SATA I / SATA II hard drive. Removable trays for fast access of additional hard drives and easy trouble shooting. SAFE 33 / SAFE50 creates two hard drive volumes where 1/3 or 1/2 of the hard drive volume is used for mirroring and the rest is used for spanning (Big). Temperature controlled cooling fan for quieter operations. Support Windows, Linux, and MAC OS X Note: For eSATA connection, port multiplier support required