Supported System Software: 7.1.1, 7.5, 7.5.1, 7.5.3
SCSI: HDI-30
Serial Ports: 1
Sound Output: stereo 16 bit.
ADB: 1
Ethernet: AAUI-15
Machine Gestalt ID: 72

Minutiae:

Japanese model which is functionally a 540c with a cool jet black case.

Apple sometimes advertises this as a 66 MHz machine, since the clock speed is doubled inside the processor chip.  However, all I/O to the processor is done at 33 MHz. 

10.4” color active matrix LCD - 16 bit (thousands colors) Display.

One of the configurations sold by Apple contains 12MB of memory.  This configuration requires the removal of the factory-installed 8MB memory module in order to upgrade to a larger capacity memory module.

Original Enabler: PowerBook 550 enabler

Serial Port with the phone icon supports synchronous modems, with handshaking on both the output and input.

Has 2 MB ROM and a 1.44 MB SuperDrive.