The ASCO Series 390, also known as 8390, are pressure-operated, remote-controlled valves with discs for industrial fluid media. Pressure operated valves use external air to operate the opening and closing of the valve. The signal air will create the demand to change the position of the valve. An anti-water hammer design has fluid entry under the disc for quiet operation. The valves feature long service life in high-cycling applications. A wide range of piston-type operators (63 - 90 -125 mm diameters) are rotatable through 360° for maximum performance at different minimum pilot pressures. The 390 Series is suitable for automotive, bottling, commercial laundry equipment, and heating and cooling circuit applications.