Receptacle With Aja Mounting Box | 3 in Dia X 4 1/2 in Length, 1 in Thread Length, Concretetight | Controls 5 a Fan. Rotate On/off; Rotate to Adjust Fan Speed. Fully Variable (For Use With Multiple Ceiling Paddle or Exhause Fans). Factory Set Minimum Speed | For Reverse Service (Generator Applications)Furbay Electric Supp