Additional storage expansion allows you to add a second hard disk drive to your notebook computer. The ThinkPad Ultrabay HDD Adapter gives you maximum storage flexibility with your ThinkPad Series. This adapter lets you add a second hard disk drive to the Ultrabay 2000, enabling 36GB of disk storage. With second HDD in your Ultrabay 2000 and included backup software, you have the fastest way to back up key applications and critical data to your second hard disk drive.