Power Acoustik NB-4 250-Watt 4-Way Mount Tweeter Niobium rare earth ferroelectric transducer magnet Polypropylene diaphragm Freq. Resp. 5Khz to 25Khz 20W Tweeter 4-way mount tweeter Niobium Rare Earth Ferroelectric Transducer Magnet Polypropylene Diaphragm Freq Resp: 5 Khz2 Khz