This epoxy coated, cast iron, overflow roof drain features and flashing clamp with an integral 2 in high external water dam, a self-locking ductile iron dome with 137 sq-in of free area and a 3 in no hub outlet. It can be purchased BAA compliant. Other options include galvanized body and flashing clamp, a sump receiver, an underdeck clamp, deck flange with adjustable extension, side outlet and a variety of domes.