The Dell Vostro-5581 Laptop Supports Single and Dual Drive Configurations. (One 2.5" Solid State Drive or Hard Drive and/or One M.2 NGFF (2280) or (2230) Solid State Drive) Note: The M.2 slot supports M.2 (2280) and (2230) Drives by moving the drive mounting bracket to accommodate the form factor. If the 2.5" Drive was not installed from Dell, you will need the 2.5" Drive caddy p/n NFX6N and cable p/n YG73X for installation. (The M.2 slot supports SATA and PCIe NVMe Solid State Drives)