The Lenovo V155-15API Laptop Supports up to 3 Drives. (One 2.5" Solid State Drive or Hard Drive in the Internal Primary Bay and/or One M.2 NGFF (2280) or (2242) Solid State Drive and One 2.5" Solid State Drive or Hard Drive in the Optical Drive Bay) Note: The second 2.5" Drive replaces the optical drive when Installed. If installing the second 2.5" Drive in replace of the optical drive, you will need the 2nd HDD Bay p/n 5M20S27909 and the 2nd HDD Board p/n 5C50S24928 for installation. The M.2 (2242) Drive uses a adapter bracket p/n 5B40S21899 to accommodate for the larger M.2 (2280) slot. If the 2.5" Drive was not installed from Lenovo, you will need the 2.5" Drive caddy p/n 5B40S21897 and cable p/n 5C10S30003 for installation. (The M.2 slot supports SATA and PCIe NVMe Solid State Drives)