The Essex Fluid Controls Watchdog® line of Thermal and Electro-Thermal Actuators are the only Actuators that operate Valves automatically in an emergency AND lets you operate the same Valves manually in day-to-day service without voiding or tampering with the fusible link. Hand-crafted, field-proven, and FM Approved, Fluid’s Actuators can be fitted on our series of Ball, Butterfly, and 3-Way Valves, or on your customized design. Contact us for a no-obligaton quote.