The ASCO Series 159 Motorized Actuator is offered in On/Off and High/Low/Off construction. The motorized actuator is a self-contained, electrohydraulic linear actuator featuring dual internal control valves for repeatable positioning. When the actuator is mounted to a Series 158 valve, position indicators on both sides of the actuator show the open or closed position of the valve. The Series 159 Motorized Actuator and Series 158 gas valve combination provide a globally approved safety shut-off solution for a wide range of applications including boilers, furnaces, ovens, dryers, incinerators, thermal oxidizers and other heating systems