Marine Audio Pro

Polk Audio MM651 UM For 35 years Polk Audio has been committed to enhancing everyones entertainment in speaker sound, so when Polk Audio decided to build a marine certified speaker; they did it in a way that only Polk Audio knows how: BIG. Polk Audio introduced a very qood quality speaker called the MM651 which was already marine certified, and then they modified it more to build the MM651 UM. UM stands for Ultra Marine. The biggest changes to t...