The exterior design The CM 690 II Advanced case is mainly made of steel, mesh and a bit of plastic, illustrated by the picture below. Cooler Master has done a nice job design wise, and the two silver stripes create a nice contrast. The mesh isn't just for looks, it also provides passive cooling of the internal components.
It's possible to install 4x external 5.25" drives in the front of the case. It's also possible to use one of these bays for an external 3.5" drive by using the bundled adaptor.