The Dell Studio 17 (1749) Laptop Supports Single and Dual Drive Configurations. (Two 2.5" Solid State Drives or Hard Drives) Note: If installing the primary 2.5" Drive, you will need the 2.5" Drive (HDD1) primary drive caddy p/n 1F40K for installation. If installing the secondary 2.5" Drive, you will need the 2.5" Drive (HDD2) secondary drive caddy p/n J7P67 and the interposer connector p/n C49RW for installation.