Listen Technologies’ LA-409 neckband headphone features dual, over-ear speaker design to offer improved noise isolation and increased clarity in high-noise environments. This listen-only headset is suitable for a wearing hard-hat or safety helmet. Headphone Impedance 32 ohms Headphone Bandwidth 250 Hz - 4 kHz Noise Reduction Rating (NRR) 25.5 dB Cable Length 99 cm (39 in.) Connector 3.5mm stereo mini-jack Unit Weight 454 g (16 oz.)