Siemens GRD321.1U DAMPER ACTUATOR | SPRING RETURN | 230 VAC | ON/OFF | 30 LB-INSiemens GRD321. 1U Damper Actuator Spring Return 230 VAC On Off 30 lb inFire and Smoke Damper Actuator 30 lb in, Spring Return, 2 Position, 230V GRD321. 1U 30 lb in, Spring Return, 2 Position, 230V, Fire Smoke Additional Information Actuator TypeElectronic Fire and Smoke Actuation StyleRotary Control or Fire Smoke TypeFire Smoke Control Damper Electronic Fusible Link (EFL)YES Plenum or Standard RatingStandard Torque30 lb in Fail SafeYes Spring return