The Asus N751JK Laptop Supports 1, 2 or 3 Drive Configurations. (Two 2.5" Solid State Drives or Hard Drives and/or One M.2 NGFF (2280) or (2260) Solid State Drive) Note: If the 2.5" Drives were not installed from Asus, you will need the 2.5" Drive caddy p/n 13NB06K1AM0211 for installation. The M.2 slot supports M.2 (2280) and (2260) Drives by moving the mounting screw to accommodate the form factor. (The M.2 slot supports SATA and PCIe AHCI Solid State Drives)