The Asus ROG G751JL Laptop Supports Single and Dual Drive Configurations. (One or Two 2.5" Solid State Drives or Hard Drives) or (One 2.5" Solid State Drive or Hard Drive and/or One M.2 NGFF (2280) Solid State Drive using a M.2 bracket Installed in the second 2.5" Drive Bay) Note: There are two 2.5" Drive bays in this machine. The M.2 Drive uses a bracket p/n 13NB06F1M04011 and is installed in the second 2.5" Drive bay. If adding the second 2.5" Drive, you will need the 2.5" Drive caddy p/n 13NB06G1AM0301 for installation. (The M.2 slot supports PCIe AHCI only Solid State Drives)