File:12x and 4x Apple CD-ROM drives.jpg

The back of the Apple CR-507-C (12x speed, top) and CR-504-L (4x speed, bottom) CD-ROM drive mechanisms which both featured an internal 50-pin SCSI interface. The bottom unit is from a Pippin Atmark console, which shared similar components as Power Macintosh systems.

Source

 * Un lecteur CD plus rapide dans la Pippin (et un échec partiel) (French) by Pierre Dandumont, Le Journal du Lapin. 2016-09-03.