Comes with Mac OS 8.5. This extension allows your Mac to mount and read CD and DVD discs. You will need it if you have an Apple CD-ROM or DVD-ROM drive. This driver replaces Apple CD-ROM and Apple DVD-ROM, which are no longer necessary. If you aren't using the CD-ROM drive, feel free to disable it for a few K of extra RAM. Note that this extension doesn't work with non-Apple drives. Unnecessary if you do not have CD-ROM drive.