Models without any drive bays that are based on the 12x 3.5" chassis (feature code AVQ) include the Right EIA Latch with FIO (USB ports, status LEDs, and a power button). These models support adding drive bays by using the 3.5" 8-drive backplane kit (4XH7A877) or 3.5" 12-drive backplane kit (4XH7A8771).