The HP 15 Notebook 15-ac155ng Comes in 2 Different Drive Options from HP and Supports Single Drive Configuration Only. (One 2.5" Solid State Drive or Hard Drive) or (One M.2 NGFF (2280) Solid State Drive using a Adapter Board) Note: When the M.2 (2280) Drive is installed, the M.2 Drive occupies the 2.5" Drive bay using a adapter board. If replacing the M.2 Drive for a 2.5" Drive, you will need the 2.5" Drive bracket p/n 813949-001 and cable p/n 830311-001 for installation.