This Hard Drive silencer helps to reduce vibrations made from high spinning hard drives. On the bottom of the unit are four rubber pads that the hard drive rests on. Simply attach the included bands around the four posts on each side of the unit to hold it in place. There is also a cable to ground your hard drive to prevent static shock. This unit fits in a standard 5.25' bay. An optional 80mm fan can be attached to the bottom to help cool your hard drive. The optional fan will take up another 5.25' bay, so make sure that you have two bays ready. So keep it quiet with this Hard Drive Silencer.