If you want the best possible sound in your car of the standard car stereo or of an amp the In Phase XTC range it the best you can get. Using state of the art materials only speakers at twice the price use, the In Phase XTC are Superb; Kevlar and Silk are just some of the materials used to make these great speakers. Also the tweeters can move 360 to improve the sound. 400Watts, 90bB Sensitivity so they can give a massive sound from any car stereo, multidirectional tweeter to point the sound into the car and towards your ears and not at your feet like most other speakers. 400 watts RMS. 400 watts max output. Mounting depth 8cm. Size 22cm.