Selenium ST400TRIO Super Tweeter Black Selenium's ST400 super tweeter offers brilliant, long throw high frequency enhancement for larger venues, night clubs, DJ rigs, and other pro speaker system applications Rugged and attractive cast aluminium housing, Durable phenolic diaphragm provides smooth, non-fatiguing response; FEA-optimized magnetic circuit reduces distortion and increases output Tightly-controlled 40 conical dispersion for maximum SPL and throw; Use of high temperature adhesives and materials increases power handling