Polk Audio DB651 6.5"/6.75" 2-Way Marine Certified db Series Car Speakers with Liquid Cooled Silk Tweeters. Step up your vehicles audio performance with Polk Audio's revolutionary db651's. Cutting edge technology has allowed for an efficient speaker that has ability to accurately reproduce music like you have never heard before. A precise balance of materials including the Silk/Polymer Dome tweeter and Mica Cone woofer enable smooth roll-off and quick response at any volume. The rubber surround adds to bass response as well as increases the lifetime of the speaker under any conditions. Being marine certified, the Polk DB651's will surprise you with its versatility and ability for use in many applications. The high-efficiency loudspeaker means less power is necessary for the same quality output. The revamped db Series delivers that perfect Polk Audio performance and durability like never before.