The internal earphone is thin, does not squeeze the ear, and is comfortable.The main unit contains a larger capacity battery up to 450mAh, which makes the standby time and working time of the whole machine longer.Fix the main unit with screws and bayonet, which makes the main unit installation tighter and high-speed riding is not easy to fall off.Use high-power audio amplifier to make the audio volume range larger, and it will not affect music playback and telephone answering in the noise environment of high-speed riding.Use high quality amp chip to restore bluetooth-compatible audio with high sound quality.Type: Motorcycle Helmet IntercomBluetooth: 4.1 + EDR CSR8635Support Protocols: A2DP/AND/AVRCPBattery: 450mAh Lithium Battery (Included)Charge Voltage/Current: DC 5V/190mAFrequency: 2.4GHzAmplifier: HT4832SQWork Time: about 10 HoursPhone Connection Distance: 50mFeatures: Wireless, Easy to Install, with MicLength: 8.5cm/3.35" (Approx.)Width: 5cm/1.97" (Approx.)Height: 2cm/0.79" (Approx.)Notes:Due to the light and screen setting difference, the color of item may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Motorcycle Helmet Intercom1 x Microphone1 x Charge Cable1 x User Manual1 x Install Tool3 x Sticker