MBQUART ZK1-169 6 x 9 2-Way Coaxial Car Speakers, Black Ceramic coating helps reduce overtones and harmonic distortions that can occur when using Titanium at higher power levels. Tweeter assures system produces highest sound quality with lowest distortions 12db high/low pass crossover on coax hidden in the pole of the tweeter make critical frequencies seamless and distortion free Removable phase lens allows Dispersion Tuning which permits the listener to widen or narrow the width of the sound stage depending on the chosen mounting location Z-Line tweeters are mated to a Nylon Surround which dramatically reduces the Fs specification. Subsequently, you will hear very smooth high frequencies, even when pushing the system hard Euro-DIN - Unique shaped mounting brackets and holes to accommodate OEM and custom installations for midrange