The hot swap drive bays are a huge feature of the Cooler Master iTower 930, and therefore deserve a section of the review just for them. We saw a glimpse of the drive bays towards the beginning of the review, now let's take a closer look.
A single drive tray is shown in the images below. The material of construction is plastic except for a steel brace shown in the below left image, which has to be removed before installation. The front face of the trays are well ventilated to allow the rear mounted fan to draw air through, and the blue handle releases the tray from the case in order to swap out drives.
On their own, the trays are rather flimsy, but once a drive is secured (using up to four screws), the assembly is completely rigid and ready for use. The below left image shows a Seagate 500GB drive installed in a tray, and the below right image shows it about to be locked into the case. Installation of each drive is quick and easy, and they slide in smoothly with a slight "click" to let you know it is in place.
The empty drive bays are shown in the below left image where you can see the power and data connections at the very back. At the top of each bay (in this orientation) there are also two LEDs which indicate drive power and activity. "Light tunnels" transfer this light to the front of each tray so that it is visible externally, while eliminating the need for extra wiring.
The back side of the drive bays is shown in the above right image, where a handful of connections can be seen. All four drives receive their power from just two 4-pin Molex connectors, making wire management and the availability of power connections a minimal concern. Some 4-bay enclosures require a power connection for each drive, which just seems unnecessary and messy. In addition to powering the four drives, you can power up to four fans thanks to the 3-pin fan headers found just below the two 4-pin connectors. There isn't room for extra fans in this system, and since the exhaust and drive fans have 4-pin connectors, I don't really know what you would do with these connections, unless you connected your CPU, chipset, or VGA fan to these, instead of directly to your motherboard. The blue SATA data connections on the back of the bays correspond to the bays from top to bottom by connecting cables from left to right. IE, the left connection is for the top most bay. There is also a set of jumpers that can be used to configure whether the signal transmission is from the device or the host.
To keep your drives cool, a 92mm fan gets mounted to the back side of the bays. As shown below, the fan is attached to a blue plastic frame which clips on to the drive bays and is secured with one thumb screw. This fan is not only for your drives, but it the only thing close to being an intake fan for the system.