The Dell Latitude 14 Rugged Laptop (5424) Supports 1, 2 or 3 Drive Configurations. (1 or 2 Drive Configuration: One M.2 NGFF (2280) Solid State Drive in the Primary M.2 Slot and/or One M.2 NGFF (2280) Solid State Drive in the Secondary M.2 Slot) or (3 Drive Configuration: One M.2 NGFF (2280) Solid State Drive in the Primary M.2 Slot and/or One M.2 NGFF (2280) Solid State Drive in the Secondary M.2 Slot and One 2.5" SATA Drive or M.2 (2280) SATA Drive in the Optical Drive Bay) Note: When a 2.5" Drive or a M.2 Drive is installed in the optical bay, they replace the optical drive. The 2.5" Drive and the M.2 Drive use different removable caddys in the optical drive bay. (The primary and secondary M.2 slots on the system board support SATA and PCIe NVMe Solid State Drives. The optical bay supports SATA only Drives)