Scan-Speak Illuminator D3004/6020-00 1" Textile Dome Tweeter, 4 ohm 1" Textile Dome with Large Roll Surround for Wide Dispersion Patented Symmetrical Drive (SD-2) motor Shallow Non Resonant Alu Rear Chamber Ring Neodymium Magnet 61.9mm (2.44") diameter flange with 21.5mm (.85") depth