Multi-Mount Tweeter: Included Flush or Surface Mount Adaptor and can Swivel within Adaptor for Superior Imaging To The Next Level The THUNDER Series speakers are designed to take any car audio installation to the next level while delivering a full-range, sound experience for all types of music. This unit features a polypropylene woofer and soft dome tweeter that offer excellent clarity and imaging. The included crossover includes a two position tweeter adjustment of 0dB or -3dB allowing the user to customize the sound based on their preference.