Introducing the MB994SP-4S, a full metal mobile rack backplane, capable of storing four 2.5" SAS / SATA SSD & HDD 6Gbps in a 5.25" device bay. This product is constructed of heavy duty metal to hold up in the toughest of conditions. It includes a LED is placed on the front of each drive tray and dual 40mm cooling fans to keep the drives running in at optimal temperatures, in even the most intense applications. The included EZ Slide Mini Trays also allows multi drive interchangeability between other compatible Icy Dock products. This device is suited for applications such as: Medical & Military systems, Media servers, IPCs, HTPC, and All-In-One computers.