Nantucket Sinks 3.5EDF-MBL extended flange is perfect for use with fireclay sinks or garbage disposals. For ISE type units with 3-3/8 I.D. Spring loaded center post for smooth strainer operation. Matte black finish coordinates with many of Nantucket Sink’s matte black Vineyard Collection matte black sinks or your chosen kitchen hardware! (installation required – garbage disposer is not included with drain).