The Lenovo ThinkPad T540p Laptop Supports up to 3 Drives. (One 2.5" Solid State Drive or Hard Drive in the Primary Drive Bay and One M.2 (2242) Solid State Drive for Caching and One 2.5" Solid State Drive or Hard Drive in the Optical Ultrabay Slim) Note: The second 2.5" Drive replaces the optical drive when installed. If installing the second 2.5" Drive in replace of the optical drive, you will need the ultrabay slim tray for installation.