The large, professional 40 mm drivers with a frequency range from 18 Hz to 20 kHz reproduce every nuance, but also exceptional detail. Mix with confidence thanks to neutral sound signature and accurate sound reproduction; 32 ohms; 110dB SPL/V. A self-regulating helmet holder and ...The large, professional 40 mm drivers with a frequency range from 18 Hz to 20 kHz reproduce every nuance, but also exceptional detail.