CSR Bluetooth Chip: It can realize full-duplex intercom with the highest ideal speed of 80km/h-110km/h and the longest distance of 800-1000m (unobstructed). When Bluetooth is connected to the mobile phone, priority switching between phone, intercom and stereo music can be performed. Example: When intercom, it can automatically answer incoming calls, and can automatically resume intercom after hanging up. Noise cancellation technology: DSP echo cancellation and noise suppression technology ensure clear voice quality at high speed. Easy hands-free communication: support to make or receive hands-free calls, listen to stereo music, make FM radio or use GPS navigation with Bluetooth V3.0 wireless technology. All functions can be switched freely. Also provide 2.5mm audio jack as wired connection, so you can connect BT-S3 to mobile phone, tablet PC, GPS or other capable devices. Convenience: Suitable for all full-face helmets and most half-mask helmets that can cover the ears. A larger push button makes it easier to use, even with gloves. And it adopts the buckle type connection between helmet and clip, easy to assemble/disassemble. Excellent waterproof: Waterproof all-silica gel is adopted. Even in rainy or snowy days, it will not affect your use and make your outdoor riding more exciting. Number of shipments:; 1 x intercom 1 x USB cable 1 x microphone and speaker 1 x key 1 x headphone clip with fixing screws 1 x Headphone Clip 1 x Audio Cable 1 x User Manual