This is a high quality aftermarket Samson 9-BM1CD34TI0000 High Frequency Diaphragm For Samson CDR34 Driver Use In D412 And D415 Enclosures & More Please Look And Make Sure The Diaphragm You Are Ordering Matches The Pictures Above & The Specs Below Overall Diaphragm Diameter: 3 1/8" (79.4mm) Voice Coil Diameter: 1 3/8" (34.4mm) Nominal Impedance: 8 ohms