Bluetooth handsfree kit helmet headset bluetooth version bluetooth 30 talk time 12 h standby 700 h call functions pairing music playback time redialing dimensions lxwxh 9 x 45 x 2 cm transmission mode duplex full duplex series cellular line interphone mc power supply li polymer assembly type helmet audio functions speech synthesis text to speech fm radio with rds digital signal processing dsp bluetooth profiles a2dp avrcp display without rang