Galvanized construction, externally braced for added strength. Heavy-duty construction ideal for coastal and high wind areas. Simple, 2-piece assembly for faster installation. Permanently lubricated dual bearing system for long lasting performance. Stainless steel ball bearings. 720 CFM air movement. No.GC12E Dade County Approved 02-0524.03. Nos.GC12EF & GC12EWWF Florida Building Code (FBC) Approved FL5027.