Speed nut and vibration damper included. Uses: Domestic refrigerator and freezer fans, commercial refrigeration equipment, room and hood ventilators, room heaters, evaporative coolers, humidifiers, dehumidifiers, and other equipment having 6 inch to 10 inch fan blades. These motors are used in hundreds of applications such as grocery stores, restaurant, party stores, taverns, walk in coolers, food and beverage display cases and many others.