This 12" (305) diam. roof drain is fitted with a flashing clamp that makes a watertight, puncture free bond with roofing materials. It is constructed of corrosion resistant, Duco coated cast iron and topped by a polyethylene dome and a 4"(100) stainless steel, perforated gravel guard that keeps the drainage system free of debris. This drain is engineered for a long service life and designed for installation in flat roofs requiring a medium size drain.