Zoom Bluetooth Stereo Headphones & 3.5mm Jack Transmitter Bundle. Ear coupling: supraaural, Headphone frequency: 25 - 16000 Hz, Headphone sensitivity: 102 dB. Connectivity technology: Wireless, Wireless technology: Bluetooth, Wireless range: 10 m. Dimensions (WxDxH): 145 x 50 x 135 mm. Battery life (max): 12 h, Battery technology: Lithium-Ion (Li-Ion). Quantity outer carton: 33 pcs