This is a removable disc pack made by the Caelus division of Electronic Magnetics and Memories. It is a single platter cartridge in a white plastic top shell that has a molded handhold to aid in insertion of the cartridge into the drive, and an access panel on the opposite side where the read/write heads are inserted. The bottom is black plastic with a brushed steel hub in the center, and small wedge-shaped, spring-mounted metal access panel (which may have been used to blow air in). There is also a small cut-out under the handhold that exposes the raised edge of the hub, which has slits in it to enable orientation of the disk platter
