1. Physically design which places the speaker outsides of the ear canal to eliminate the discomfort for the foreign body, easeful than the traditional inner ear bud.
2. Mechanically design which creates the best sound resonance effect.
1. Ear-clip type.
2. Flexible microhpone arm.
3. speaker spec. 110dB+-3dB; microphone spec. -62dB+-2dB.
4. Any color can be made.
5. Popular phone models are available.