DDB and DDD Series Direct Coupled Actuators are non-spring return actuators that are perfect for positioning of dampers and valves in HVAC systems. DDB actuators are designed to accept floating control signals and come in a variety of power supplies. DDD actuators are designed to accept 4 to 20 mA or 0 to 10 VDC modulating control signals and are 24 VAC powered. Actuators produce 88 to 265 in-lb (10 to 30 Nm) of torque. Contact factory for optional internal auxiliary switches on DDB.