Looking at the bottom of the case you can see the
unique shape of the soft rubber non-skid feet used on the RC-690 and
located in between the two sets of legs you have the opening for the
power supply which will allow outside air to be brought into the
unit.
Located on the bottom of the RC-690 is a mounting bracket that will hold a fan up 140mm in size. surprising we ran into a problem using our Mushkin power supply whereby we could not use a fan in the bracket or the fan would block the pair of PCI-e connectors on the power supply as you can see by the photo below.
Cooler Master happens to have one of the coolest methods of holding devices in their drive bays, first you install the device with locking latch lifted up. Align the holes on the device with ones on the drive and the close the latch and lock it in place. If the need for screws would arise you have all the screws you will need screwed into the drive cage.
