Neckband Headphone for iPhone,iPod & PC,with Microphone Speaker Dia:40mmPower input:40mwCord Length:2.1mSensitivity:112±3dB Frequency response: 20∼20khzDesign for MP3/MP4/Portable mediaimpedance:32 ohmMic Sensitivity:-58±3dB Our company and procedure information: Neckband Headphone for iPhone,iPod & PC,with Microphone