Titan's TTC-HD90 is a hard drive cooling device, which has a dual purpose: Besides dissipating heat from the hard drive surface, it can also dampen the noise level of the hard drive. The device is made of aluminum, but uses noise dampening contact pads that conduct heat efficiently.
You need to remove the protective covers from the contact pads before you put your hard drive into the TTC-HD90. Pay attention to the orientation of the top and bottom part of the device. It can only be closed properly one way, and the process can be difficult. The top and bottom covers have a small curb along the side. This curb fits into a trench on the counterpart. There are four screws that firmly attach the two components. Since this device is supposed to be installed into a 5.25" drive bay, there is a small front panel, which you can now install as well. The back side remains open.
We used a WD740ADFD hard drive to look at the efficiency of this product. Since the drive runs at 10,000 RPM and easily reaches 50°C when operated without cooling, we were skeptical at first. But the TTC-HD90 actually managed to reach a drive surface temperature of 36°C when the drive ran idle for over two hours. We used a laser-assisted IR thermometer to find hot spots - but there really were none. Clearly, the Titan HDD cooler device does its job.
The noise dampening effect is a byproduct of the structure, since an aluminum enclosure, which is almost fully sealed, is suitable to insulate noise by itself. The materials used inside also contribute to the result: We only heard the WD Raptor drive when we got close to the TTC-HD90, or when there was heavy I/O activity.