ARD (Automatic Round Damper), 5-inch, with 24-volt (AC), spring-return damper motor ensure low leakage while controlling circulating air in heating, cooling, and ventilating systems. Damper is shipped as powered closed/spring return open damper for use with TotalZone Damper System, Electronic MiniZone Damper System and other normally-open damper systems. Damper can be field-converted to power open/spring return closed damper when used as independent zone or for fresh air intake for ventilation or combustion make-up air.