... Wireless connection among such three parts.Fetures:1. All digital and encryped technolgoy applied2. Effective transmission distance is ... Speaker, Volume -/+, Brightness control -/+, Antenna, Power ON/OFF Switch , Work Light, Charge Light- Dimensions: L:102 x W ... Microphone, Call button , Speaker, USB interface for charge , Power switch , ‘Pairing’ button, Indicating light for low voltage , Indicating ...