External Appearance II
The top half of the case, at the back, is dominated by the PSU space, ATX backplate space and a large 120mm fan mount space for internal case cooling. Further down sees the I/O card spaces and a second PSU mounting area. That's correct, the Stacker fully supports two PSU units in your system. You'll see that more clearly when we look at the internals.
The left side of the case, as with the large majority of the rest of the chassis, is made from aluminium. It has a round mesh section that lies over the mainboard area inside the chassis. The mesh allows you to mount a cooling fan on the inside, to cool the mainboard section.