Innovative two-door construction offers many advantages over the conventional four-door design. Designed for ease of installation, our smoke vent requires fewer field adjustments than a traditional four-door model. The Nystrom acoustical smoke vent can be connected to the building's life safety system. After a fire drill, a person on the roof can safely close the two doors from the top of the vent, or by using a 3-button control from as far away as the basement. Once the alarm system has been tested, it is easy to reset the smoke vent over and over again.