The Dell Precision 5550 Mobile Workstation Supports Single and Dual Drive Configurations. (Two M.2 NGFF (2280) or (2230) Solid State Drives) Note: The M.2 (2230) Drive uses a wafer adapter bracket p/n CF4TP to accommodate for the larger M.2 (2280) slots. If Installing a M.2 (2280) or (2230) Drive in SSD slot 1, you will need the M.2 Drive thermal cooling bracket p/n 130R6 for installation. If Installing a M.2 (2280) or (2230) Drive in SSD slot 2, you will need the M.2 Drive thermal cooling bracket p/n 4TW9C for installation. (Both M.2 slots support PCIe NVMe Solid State Drives)