Polk Audio DB572 5" x 7" 2-Way Coaxial Speaker for Car & Marine. The Polk Audio DB572 2-Way Speaker features a 5" x 7" polypropylene woofer cone that can also be used in 6" x 8" application, and a 3/4" silk dome tweeter with a built-in crossover, that delivers smooth and precise sound. The speakers' Dynamic Balance technology uses laser imaging to reduce resonance. This DB+ Series speaker is versatile, with mounting hardware included. The grilles (sold separately) add a touch of style to your vehicle's interior, making them a good choice for those who want to customize their installation. Polk Audio tests the DB+ marine speakers rigorously for environmental effects like sun, moisture, and extreme temperature changes. As a result, they're even certified for marine applications, making them a great choice for your boat. Polk Audio's DB+ Series subwoofers are a great value, delivering smooth, powerful bass. So, if you want to upgrade your sound system without breaking the bank, the DB+ series speakers are an excellent option. Polk's advanced technology and engineering bring out the best in class audio with powerful speaker series, smart speakers, and soundbars, allowing you to sit back, relax and listen with your heart.