A disc cassette includes a curved portion. The curved portion includes multiple ribs that define multiple disc slots. The disc slots are configured to hold multiple discs that are spaced apart by the ribs. The disc cassette further includes multiple index features positioned on an inside edge of the curved portion. The index features are configured to allow alignment of a kicker device of a disc retrieval unit (DRU) to a disc of the disc cassette to lift the disc into a disc gripper device without disturbing one or more other discs of the disc cassette that are adjacent to the disc.