Shaded pole units are furnished with a neoprene silencer for quiet operation. Motor includes speed nut and mounting hardware for installation. Unit bearing fan motors have a 1/4" x 1/2" x 20 threaded shaft. Low temperature oil. 60 Hz motors are totally enclosed for long life. UL and CSA approved. Motors are available in Cast Iron and Aluminum. Choose between Single Foot Mounting Pad, Double Foot Mounting Pad or No Foot Pad styles.