The ideal balance of a high end car audio system requires the idealmix of speaker tone, deep bass impact and clean undistorted power. The MB Quart Formula Series of speakers provide the base for a great sounding, impeccable system. These 4 in. x 6 in. Formula Series 2-Way Coaxial Speakers have aluminum dome tweeters with polypropylene cone speakers. Peak handling power on these 4 in. x 6 in. car speakers is 90 watts; RMS is 45 watts.