6-1/2" Magnetically Shielded Coaxial Marine Speakers. All Jensen marine speakers are built to deliver superior sound while turning a deaf ear to the rigorous marine environments. All speakers conform to ASTM international standards for corrosion resistance and UV exposure ensuring years of dependable service. Features: 150 watts peak (50W RMS). Conforms to ASTM B117 standard for salt and moisture resistance. Certified to be ignition protected in accordance with US Coast Guard standard 33CFR183.410. Flush mount speaker with UV stable plastic grille . Magnetically shielded to prevent disruption of marine instrumentation. Marine grade 6-1/2 polypropylene woofer cone w/ UV resistant polymer to material resist cracking and discoloration. Gold plated speaker terminals and stainless steel hardware. 19mm soft dome tweeter. 11 oz. magnet. Usable frequency: 50Hz-20kHz. Sensitivity: 91dB. Impedance: 4 Ohms: Mounting Depth: 3-7/16.