*12" Damper *Designed to operate with all 24V, 60HZ intermittent ignition and standing pilot ignition systems *Timing: opens or closes in 15 seconds *Includes 36" wiring harness for easy installation *Safety feature: dual switches *Burner can fire only if the damper is in the open position *Prevents cold air from being drawn down and freezing a coil *Prevents residual heat from being drawn up and outside *Superior corrosion protection: stainless steel construction