6-1/2" Magnetically Shielded Dual Marine Speaker. 150 Watts peak (50W RMS) power handling. 50Hz-20KHz usable frequency. 89dB sensitivity. 4 ohms impedance. 6-1/2" polypropylene woofer. 11 oz magnet. 3-7/16" mounting depth. Conforms to ASTM B117 standard for salt and moisture resistance. Conforms to ASTM D4329 standard for UV exposure. Flush mount with integral grille. Magnetically shielded to prevent disruption of marine instrumentation. Marine grade corrosion resistant ABS basket and grille. Marine grade polypropylene woofer cone. Marine grade white Santoprene surround. Gold plated speaker terminals. Myler whizzer cone.