Lenovo ThinkSystem ST250 2.5'' SATA/SAS 8-Bay Backplane Kit This ThinkSystem ST250 2.5" SATA/SAS 8-Bay Backplane Kit provides eight additional drive bays provided no optical or M.2 drives are installed. If the onboard SATA controller is used and an optical drive or an M.2 drive is installed, then at most six drives can be installed. LENOVO 4M17A12790 Designed for exact compatibility with LENOVO product, LENOVO accessories ensure maximum performance, longevity and ultimate cost-effectiveness. LENOVO accessories are an integral part of the fundamental design of its main products, combining with other key elements of their design to deliver optimum durability, reliability and quality. model : 4M17A12790 tag : HDD - SSD Accessories