mp4 earphone, high quality stereo sound.High sensitivity,10-20000Hz, 1 year warranty. stereo earphone, high sensitivity, heavy bass, high quality stereo music sound,1 year warrantyRB-B27Driver Unit diameter15mm mylar speakerFrequency Range: 10~20000Hz Sensitivity: 115dB at 1KHz Impedance: 32Ω Cable LengthAppr. 1.20M Plug : 3.5mm golden coatedwarranty: 1 year