the special stereo headphone 1.Type: stereo headset 2.Speaker: phi 40 ... .Sensitivity: 105 dB S.P.L at 1 KHz the special stereo headphone specificationType: stereo headsetSpeaker: phi 40 mm in diameterSensitivity ... needle: stereo phi 3.5 mmHeadphone desigh,simple and fashion,wear comfortableNew design,beautiful apperance,Perfect use for ipod,MP3,MP4 ...