All aluminum rust free construction. 18x16 perma -coated aluminum screen attached. Unique eyebrow designed louvers provide maximum ventilating capacity with superior weather protection. Prevents paint peeling by removing moisture from wall cavities. Provides an outlet for air movement in small confined spaces. Easy installation (drill and pop in). Available in white enamel finishes, as well as mill finish. Packaged as 12 bags of 6. 72 per carton.