The description of this product as "Holmes S1708 Bacteriostat for Cool Mist Humidifiers" is grossly incorrect. I tried to use this product but after a few minutes I started having lung pain. When I went and read the label more closely, it says that it is NOT for use in "vaporizer" style humidifiers, which includes ultrasonic humidifiers. Because ultrasonic humidifiers are typically called "Cool Mist", I was mislead into purchasing this product which is actually intended for wick-style humidifiers!