Apple 661-0121 Floppy Disk Drive. The second and newer model of Apple's SuperDrive. This 3.5" floppy disk drive has a black door and is "manual inject" (or manual insert) and used in all PowerPC Macs. Late 68K machines may also use this drive, but the cover, case or bezel will differ between "auto inject" and "manual inject", so they are not interchangeable. The last photo shows two LC III's, the top is auto inject and the bottom is manual inject - note the location of the eject hole as well.
Drive may be a Sony 2MB, Model MPF 42A (pictured), MPF 52A, or Mitsubishi MF355F. You may receive any, note that these likely do not display any Apple identification on the drive.
Drives have been cleaned, lubed, and tested to format, write, read and eject.