Beyerdynamic MMX 100 Premium in Ear Buds with Microphone (Black) (Discontinued by Manufacturer) Undisturbed communication due to excellent ambient noise blocking Transducer type -- dynamic (Neodymium magnet); Nominal SPL 96 dB Nominal frequency response -- 10 - 23,000 Hz Nominal SPL -- 102 dB Weight-optimized refined light metal housing & crystal clear, impressive Sound through Neodymium HD acoustic drivers