R50ABL 50" ALUM SQUARE ROOF VENT BLACK | Square-top metal utility vent, recommended for kitchen duct outlets and bathroom fan exhausts as well as ventilation, large capacity of full 50 sq-in of net-free ventilating area (NFA) per vent, versatile, available with square throat in heavy-duty aluminum, easy to install, pre-drilled nail holes with extra wide flashing area. CSA listed.