LEXIN LX-A4 BT Interphone Bluetooth Motorbike Motorcycle Helmet Communication Intercom Headset System with Remote Control The LX-A4 includes a remote control to allow for safe operation without ever having to remove your hands from the controls. Answer and reject calls, switch communication between riders, adjust volume, and more all within reach on the grip-mounted remote! The LX-A4 also provides one of the longest intercom ranges available with a unit-to-unit range of up to 1200 meters  almost 3/4 of a mile range! Conditions and visibility may affect range. Up to 4 LX-A4 units can be connected for rider-to-rider communications, and with up to 8 hours of talk time, the LX-R4 can be used all day long for longer rides with a small group of friends, or just with a passenger. Bluetooth v2.1 connectivity offers the ability to listen to music, receive turn-by-turn voice navigation, and make/receive calls via Headset Profile (HFP), Hands-Free Profile (HFP) and Advanced Audio Distribution Profile (A2DP). The main unit is powered by a rechargeable Lithium Ion/Polymer power cell providing 8-12 hours of use from a full charge. Digital Signal Processing forAdvanced Audio Functionality High-end HiFi StereoMusic with A2DP profile Multi point: Phone &amp; GPS Charging time:3H Standby:150H Talk time:8H