These are 1960's Vintage 12" Calrad Drivers. Manufactured in Japan by Coral, and marketed in the U.S. under the brand name 'Calrad'. These speakers are very easy to drive with tube amplifiers, and have ideal parameters for usage in open-baffle configuration. *Thick, cast-aluminum basket * Alnico magnet * 12" paper bass/mid-range cone with concentric whizzer cone for treble frequencies * durable treated-cloth "accordion"-style surround * 8-Ohm Impedance *20-Watt power rating * Approximately 95 dB/ 1-Watt/ 1-meter sensitivity * 50Hz to 13 kHz response