Each 131 speaker features a Bose full-range driver for high-fidelity sound. They provide a more consistent sound field than conventional speakers, so you enjoy the clarity and full performance of your music even when youre afloat. Bose 131 marine speakers have been designed to flush mount in the pre-cut speaker openings provided by many boat manufacturers. But unlike conventional marine speakers, they feature a proprietary ported enclosure that delivers smooth, consistent low-frequency response. This innovative approach compensates for unpredictable environments behind the mounting locations that can diminish performance. Like every Bose outdoor speaker, 131 marine speakers are thoroughly weather tested and guaranteed to withstand snow, rain, salt spray and extreme temperatures. If they can handle abuse like this, theyll be right at home in your boat.