I want one of these 60mm fansto strap to my subwoofer amplifier. Right now I've got an NMB 80mm fan running at 4.5v (less than 1/2 speed) on it and it still makes noise. Being a ball-bearing fan, it lasts a long time but is more noisy. Sunon's Magnetic Levitation system is a true innovation, causing the fan impeller to stay always in the center of its operating track and not rub against the side of the bearing during operation, for low vibration and long operating life. These are used in laptops where people can't get to the fans to replace them and the fans need to last a long time. http://www.directron.com/magnetic.html Also sold there are the Papst 8412 sleeve-bearing fans which are so well known for low noise (12 dBa).