The sink flange attaches to your sink drain opening and provides a connection to mount the disposal unit to the sink itself. If your food waste disposer is leaking, there are a few places that you should inspect. If the leak appears to be coming from around the connection to the sink, look carefully at the sink flange, as there could be an issue with the flange itself, or its gaskets. Remember to disconnect the power from your food waste disposal unit before beginning this repair. This OEM replacement part has an outer diameter of approximately 4.5 inches, and an inner diameter of approximately 3 inches.