The Lenovo ThinkPad W701 Laptop Supports up to 3 Drives. (Two Removable 2.5" or 1.8" Solid State Drives or Hard Drives in Slot 1 and 2 and One 2.5" Solid State Drive or Hard Drive in the Optical Bay) Note: The third 2.5" Drive replaces the optical drive when installed. If installing the third 2.5" Drive in replace of the optical drive, you will need the ultrabay slim media bay for installation. The 1.8" Drive uses a adapter bracket p/n 42W7888 for installation.