Description : Aluminum foil, ribbon diaphragm. Neodymium magnet, matching transformer. High SPL, 95 dB/w/m. Frequency response of 2 KHz to 40 KHz. Special Note : This ribbon tweeter is good for Hi-End. It needs individual enclosure space or use open air design to avoid airflow from other drivers damaging it. This ribbon tweeter is designed for hign frequency use. For protecting your device, DO NOT input a low frequency signal which is below 1KHz for this tweeter.