USB bluetooth onear microheadset. 2x 40mm diameter speakers. 150ohm impedance. Sensitivity of 100dB +/ 3dB. Frequency range between 100 and 6600hz. 1x Oneway microphone, ideal for voice capture. Sensitivity of 40 3 db 0dB = 1V / Pa, 1KHz. Frequency range between 100 and 10,000 Hz. Type of Microphone: Cardioid. Bluetooth 5.1. Builtin 250mAh Lithium battery. Microphone with protective foam. Comfortable and adjustable headband. Controls built into the headphones to adjust the volume. Approximately 20h operating time.