TWS headphones (True Wireless Stereo) - fully wireless BT headphones, speaker diameter: Ø 10 mm; Impedance: 32 Ω +/- 10%; Frequency range: 20 Hz - 20 kHz, sensitivity: 100 dB +/- 3 dB /1 mW (acoustic pressure level at 1 kHz); Microphone sensitivity: -42 dB±3dB, Battery type: 3.7V 50mAh Li-ion; base 3.7V 400 mAh; Connector: Micro USB; Weight: 41 g; BT: v5.0; Max. radiated power: 2.5mW / 2.4GHz - 2.485GHz