The Lenovo IdeaPad 320-15IKB (type 81BT) 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 (2242) Solid State Drive in the M.2 Slot and One 2.5" Solid State Drive or Hard Drive in the Optical Drive Bay) Note: The second 2.5" Drive is optional and is located in the optical drive bay when installed. If installing the second 2.5" Drive in replace of the optical drive, you will need additional parts for installation. If the 2.5" Drive was not installed from Lenovo, you will need the 2.5" Drive caddy p/n 5B40N82219 for installation. (The M.2 slot supports PCIe NVMe Solid State Drives)