Dayton ventilators are designed for continuous operation to exhaust foul air, fumes, odors and grease-laden vapors. Weather resistant ventilators feature a galvanized metal motor base and supports. Motor compartment is cooled by fresh outside air. Units are speed controllable for UL/cUL 705 applications only. Motors are UL Listed for Class I, Groups CandD and Class II, Groups FandG for hazardous locations.