Flat rubber washer

Using your devices, and hearing the sound of rattling is not a thing you want. If the item produces vibration, there has to be some type of isolation to prevent it from touching hard materials because they will spread it up and you will have to hear it constantly. For example, you have bought yourself a computer and you have upgraded your cooling mechanism. The fans may be new, but if they are cheap, they might be too loud and if you are using the computer for work, you will not be able to focus properly, having your productivity down. 

To remove the vibration, and the annoying sounds that come out of it, there are flat rubber washers that are meant to be placed between the vibration producer and the surrounding hard materials to act as a mediator between them. When it starts spinning, instead of buzzing, it will be totally silent. Not that this will help you focus more and do more work, but if it is placed inside your sleeping room, it will not interfere with your sleeping so you will be well-rested. There is really no point in getting cheap items that have no flat rubber washers because not that they will not last long, but they will ruin your days as well.

If the item does not ship with them included, you can always go online and find them there. You will have to know the dimension because they have to be fit snugly so they do their job properly. If they are loose there still might be extra sounds that are not supposed to and you have not finished the job. There may be color options, but they most commonly come in black because it suits electrical equipment well, and plus they are hidden so you will have no problem with theme matching.