The Honeywell ZT931 is a spring return direct coupled actuator engineered for precise and reliable control of dampers and valves within HVAC systems. This actuator provides floating (3-wire) control and features a fail-safe spring return mechanism, ensuring that the damper or valve returns to a safe position (either open or closed) upon loss of power. Designed for easy installation, it mounts directly onto standard 3/8 in. to 1/2 in. round or square jackshafts, making it a versatile solution for both new installations and retrofits in commercial buildings. Its robust construction and dependable performance make the ZT931 an excellent choice for managing air flow in VAV terminal units and other air handling applications.