The Dell Inspiron 15-5575 Laptop Supports up to 2 Drives in 2 Different Configurations. (One 2.5" Solid State Drive or Hard Drive and/or One M.2 NGFF (2280) PCIe NVMe Solid State Drive in the Internal M.2 Slot) or (One M.2 NGFF (2280) PCIe NVMe Solid State Drive in the Internal M.2 Slot and One M.2 NGFF (2280) SATA Solid State Drive in the Adapter Caddy) Note: On select models, Dell Installed a M.2 (2280) SATA Drive using a Interposer adapter caddy p/n TF3RP in the 2.5" Drive bay. If Replacing the M.2 Drive to a 2.5" Drive, you will need the 2.5" Drive caddy p/n D6J2T and the connector p/n 0KNK9Y for installation. (The Internal M.2 slot supports PCIe NVMe only Solid State Drives)