A “two-fix” rainwater drain for concrete flat roofs. The 50mm Side or Bottom Outlet F-Box with protective construction cover is set into the concrete slab. The Flange has a 110mm Outlet, which can also be fitted into a 110mm straight socket or 110mm, 90° elbow. Flange height is set to the waterproofing level after the concrete has set. Concrete surface is then waterproofed, covering the Flange with bitumen or cementitious waterproofing. Domed Grate is bolted down onto the waterproofing membrane. A permanent waterproof seal is provided for.