Case fan
A fan located inside a computer case generally attached to the front or back of the computer that helps bring air into the case and also take hot air out of the case. Computer case fans are available in a wide variety of sizes, however 80mm, 92mm, and 120mm (12cm) with a width of 25mm are the most commonly used case fans in a computer. Below is a graphic example of what a computer case fan may look like.
Also see: Case, CFM, dBA, Fan, RPM