*采用电子降噪技术，可以营造局部安静的听觉环境，在嘈杂的环境中达到清晰、高质的听觉享受 *灵敏度：102dB在300Hz时 *降噪水平：12dB在300Hz时 Noise cancelling headphoneJH-304 *active noise cancelling technology to enhance the power of noise filtering *block the external noise to offer a superb listening exerience *Driver unit:40mm Dynamic speakers *frequency response:20Hz-20KHz *active cancellation:20-1000Hz *sensitivity:102dB at 300Hz *reduction level:>12dB at 300Hz