26 mm Beryllium Dome Tweeter4 ohm, Neo, Large Chamber, Grill- 1" Beryllium diaphragm (99% pure BE)- Large non resonant aluminium enclosure- Sound transparant protective grill- Patented symetrical drive (SD-2) motor- Large roll surround f. wide dispersion- Applicable for HiFi and automotive LINK: Beryllium Safety Data Sheet