The Selenium by JBL ST400 is a super tweeter for outstanding detail and clarity in high-frequencies without harshness. The ST400 may be used individually in lower power systems or arrayed for increased coverage and SPL in higher power systems and is equipped with quick coupling connectors. The base and diffuser are constructed of aluminum which contributes to better heat dissipation. The bullet-shape horn design offers a longer throw 40 x 40 degree dispersion. The phenolic annular diaphragm is long-lasting, cost effective and more natural-sounding than metallic diaphragms. The use of high-temperature materials and adhesives improves power handling and produces exceptionally high acoustic output. A precisely engineered diaphragm structure and alignment mechanism for easy, reliable, cost effective repair in case of diaphragm failure.