Universal SATA 2nd HDD HD Hard Driver Caddy for 9.5mm CD/DVD-ROM Optical Bay set Caddy Thickness:9.5mm Caddy Interface: SATA Hard Drive Interface: SATA (2.5" sata and ssd drives) This 2nd Hard Disk Drive Adapter can increase your storage. It enables you to add a second notebook hard disk drive to your modular/optical bay.