Bluetooth: Provides a more reliable and faster connection, allowing you to make phone calls, play music, or get driving directions without occasionally disconnecting. The Bluetooth FM transmitter supports voice assistance.Intelligent charging: Charging speed is 4 times faster than standard chargers, and compatible devices can be charged to 80% in 35 minutes. The Bluetooth FM transmitter can charge two devices simultaneously.This car mounted Bluetooth FM transmitter has built-in overcurrent, overvoltage, and short circuit protection, effectively preventing various problemsEnjoy simultaneous high-speed charging for driver and passenger or plug a USB drive into the top port to play saved files through your cars sound system. Short press to answer incoming calls, short press to hang up and dial again, long press to reject calls, short press twice in a row to redial the last dialed phone number, rotate to the right once to select the next song when playing music, rotate to the left once to select the previous song, rotate continuously to the right to increase volume, rotate continuously to the left to decrease volume, short press to play/pause music