... to 800m 2 receive cellphone call automatically motorcycle helmet bluetooth intercom headset(1) Wireless headset for bluetooth enable cell phone at ... phone. Up to 5 hours talk time when using the intercom feature. Up to 300 hours standby (2) Call out, call ... , backward, play, pause (8) Automatic switching among bluetooth cell phone, intercom, stereo music, FM radio. (9) With DSP echo cancellation and ...