Echo Suppression Headphone eliminates echo impact to the voice signal. Feature Total Harmonic Distortion (THD): < 0.5% Bluetooth Version: 4.1 Support: A2DP, AVRCP, HTSP, HTFP Communication Distance: 10 Meters Dynamic Range: 118 dB Drive Unit: 57 mm Horn Impedance: 16 Four Language Voice Prompts: English / Chinese / Spanish / French Extra Music Time Add a audio cable ...