The Asus BX303LAB Laptop Comes in 2 Different Drive Options from Asus and Supports Single Drive Configuration only. (One 2.5" Solid State Drive or Hard Drive and One mSATA Solid State Drive for Caching only) or (One M.2 NGFF (2260) Solid State Drive using a Adapter Bracket) Note: When a M.2 Drive is installed, the M.2 Drive occupies the 2.5" Drive bay using a adapter bracket with interposer board. If replacing the M.2 Drive for a 2.5" Drive, you will need the 2.5" Drive caddy and cable for installation. If replacing the 2.5" Drive for a M.2 Drive, you will need the M.2 Drive adapter bracket with interposer board for installation. (The M.2 Interposer board supports SATA only Solid State Drives)