Industrial drain connectors are used to connect roof membranes with rainwater drains. The slightly conical-shaped tang facilitates installation in rainwater pipes. The particular length of the tang extends their fields of application, making them perfect for industrial uses when long lengths have to be connected. The elastic material from which they are produced guarantees a long-lasting seal. Knurling at the top of the tang ensures a perfect attachment of the Leaf-Excluders and Gravel-Excluders to the drain connector. They have excellent resistance to deterioration caused by the sun, ozone and other atmospheric or chemical agents normally present. The elasticity of the raw material from which they are made allows for excellent flexibility even at low temperatures, enabling the mechanical and physical characteristics to remain unchanged for a long time. The completely smooth flange improves the join with the synthetic sheet. The drain connector is perfectly compatible with prefabricated EPDM synthetic sheets. Thorough cleaning of the drain connector and the synthetic felt is recommended near the connection area to the drain connector.