This BIM can be used to ride a motorcycle and in the back seat of People ，BIM with four Bluetooth devices: the phone with a Bluetooth-enabled， two BIM (two driver， or a driver， a person in the back seat)， with audio a multifunction device's built-in or external Bluetooth transmitter， this BIM is designed for motorcycle and ski enthusiasts designDescription: The product does not contain helmet， helmet in this product for illustrative purposes only.M1 is designed for motorcyclists helmet design and development of a stereo Bluetooth headset， it has connected more than 150 meters， you can connect two Bluetooth devices at the same time， if at the same time with two M1 stereo Bluetooth headset， at 150 metersThey can talk to each other inside. While M1 includes CVC DSP noise reduction and echo cancellation technology， so you can properly call high speeds.Product Features:1) The maximum distance calls between two riders up to 150 meters， between the three riders in the real two-way wireless Bluetooth communication system2). 120 km above the operating speed may be normal call3) wind， rain design， all-weather use4) Stereo music / audio function (using the A2DP transmission phone / MP3 / GPS)5). DSP noise cancellation6). CVC echo cancellation function7) can be used as a mobile phone using Bluetooth hands-free headset8) two-way full-duplex wireless intercom function9) Wear simple and convenient， without having to install Main specifications:1) Bluetooth version: Bluetooth V2.1 and compatible with V2.0 and V1.2 standards2) chip:. CSR BlueCore5 stereo chip3) Transmission distance:. 10M (Class2)4) Frequency:. 2.4 GHz5) Weight: 46g6) Standby time: 100 hours7) Talk time: 6 hours8) Charging time: less than 3 hours9) Power supply:. DC5.0V / 120Ma10) Battery type: Built-in rechargeable lithium battery11) Operating voltage: 3.3--4.2V12) Overall Color: Black13) Applicable models: compatible with all major brand Bluetooth cell phone and Bluetooth GPS