Liberty Industries supplies a solenoid valve form the worlds leading manufacturuer, ASCO, to connect to the 100FJR, 2001TB and 351 Bull Dog shoe brush machines to a central vacuum system. This valve is used in conjunction with a central vacuum system to regulate the flow of air or vacuum pressure. The valve is normally closed and opened when energized typically when the shoe brush machine is energized. The standard model is 120 volt, 60 HZ, single phase rated. Other voltages are available when required.