Kingston Air powered, valve actuators are designed for use with selected Kingston Valves where remote control is desirable. The actuator.valve combination is well suited for use in areas where explosive gases may be present. They are an effective alternative to the high priced, explosion-proof, electrically operated valve. The 331 Actuator is used with 305A, 305B, and 425, and available in 1/2" through 1-1/4" sizes.