Correct placement is also very important, "24V DC Cooling Fan" from the human body should not be too close, too close to the hair so that the blood circulation and sweat circulation gap is too large, the nerve center will be out of balance, once the time is too long, the various organs of the body will feel tired, so general discomfort. Best of "24V DC Cooling Fan" placement of about two meters away from the body, making even more gentle wind. When the wind should not open too much sleep, during sleep, the body slows down circulation of people, but this time the body is most vulnerable when facing the body of excessive wind blowing, it will cause the body extremely suited appeared human weakness symptoms appear severe stroke. Fan noise is the main component manufacturing motors, in the selection of "24V DC Cooling Fan" must listen whether the noise when the motor is running, to see it in operation whether stable; good motor let you in quiet environment, only to hear the wind, "whispers", ultra-quiet fan blowing air is good.