Product Dimensions- LxWxH (in inches) 9" x 9" x 5. Efficiency- The DIA-XT8 sounds great with just instrumentals, and, even better with vocals. Get the most out of your system by upgrading to a speaker that gives you everything you're missing from your stock car stereo. Powerful Sound- With 550W max power and 275W RMS, the DIA-XT8 provides enough power to tackle a full range of audio. Single Voice Coil (SVC)- This high strength voice coil built with Kapton can handle high power applications. High Quality Design- Black Diamond utilizes only the best materials to provide you with high quality sound you can trust.