"On of the many great features of the case is the snap-in fan headers. These are shown below, and are the purple plastic items, clipped to the side of the case. There are 4 of these in total inside the case, 2 at the front, and 2 at the back. As standard, 2 x 80mm fans are provided in the rear of the case (the other 2 are optional). To swap the configuration, all you need to do is unclip the fan out (no screws), and simply push it into the alternate header - its as easy as that. Once you have the configuration you want, you connect the molex power connectors to the power supply."