The FatCage MB901SPR-B R1 is a dual bay RAID 1 & JBOD enclosure that supports 2 x 2.5" SATA SSD/HDD or 3.5" SATA hard drive in a 2 x 5.25" optical drive bay of your computer/workstation/rackmount system. The MB901SPR-B R1 is equipped with built-in hardware RAID chipset and easy-to-read RAID status LED indicators, letting you effortlessly mirror the 2.5" or 3.5" drives for data redundancy and monitoring the RAID status without pairing with a RAID card or using RAID monitoring software. In addition, the built-in RAID chipset does all the calculations without using the system resources, which improves the system's performance compared to motherboard RAID or software RAID. Finally, the removable drive trays and hot-swap feature let you replace a failed drive without shutting down the system, making the MB901SPR-B R1 a perfect drive enclosure for any mission-critical computing system, such as industrial automation systems and file server systems.