The OPTIBT38 is a 400-watt, die-cast aluminum tweeter from Lanzar that really gets the highs rolling. With a frequency range of 2.5 to 20 kHz, you’ll have the top end covered. A 1.5 inches high-temperature Kapton voice coil and Neodymium magnet provide rich, sweet highs completely free of distortion. The die-cast frame ensures the security and longevity of your equipment. 4 ohm impedance.