The MobileSTOR MS2UTN+B series is a fully loaded 2-bay external RAID solution designed for home and small business storage needs. With simplicity and flexibly in mind, this series is equipped with two hot-swappable 3.5" hard drive trays, as well as both USB 2.0 and eSATA host interfaces. In addition to RAID 0 and RAID 1, MS2UTN+B also utilizes the latest Silicon Image 5744 chipset, supporting the newest SAFE33 and SAFE50 technology. SAFE33 and SAFE50 allows the creation of two hard drive volumes where 1/3 (SAFE33) or 1/2 (SAFE50) of the volume is used for mirroring and the rest is used for Spanning (Big). In comparison to SAFE (RAID 1) mode, which utilizes both hard drives for mirroring, SAFE33 and SAFE50 increase storage space by setting aside a portion of disk space for regular data storage while performing mirror simultaneously. By incorporating SAFE33 and SAFE50, the MS2UTN+B eliminates the cost of additional hard drives needed for various storage modes.