we are professional manufactory in china, Our boombox are high output.high sensitivity and compact system...bring out excellent sound.make your car as a real theat. 8"/10"12" Magnet Structure30/40/40 OZ Power Handing 300/400/500W Impedance2*4 ohm Sensitivity 89dB±2 Frequency Response 35-2.5KHz Poly Injection YES Digital Ready YES Magnet Type custom vented Design..