The back and bottom The back of the CM 690 II Advanced case is equipped with 2 holes for water cooling tubes. Other than that, there's space for the motherboard I/O shield, and the 120mm exhaust fan sucks out hot air from inside the case.
The case has a total of 8 expansion slots, sadly not ventilated. The two holes to the right is used for the VGA holder. A standard power supply is supported, and can be installed with 4 screws.
Under the CM 690 II Advanced case we find some solid rubber feet, and a big removable dust filter. The air intake on power supplies has plenty of space as well, and 2x 120mm fans can be installed if you remove the bottom hard drive bay. If this isn't removed, a single 140mm fan can be installed instead.