1.3in1 Bluetooth Car FM Transmitter: wireless music streaming, hands calls, and dual USB fast charging all in one smart device. Bluetooth 5.0 stable connection: fast pairing, strong signal, and stereo sound with minimal interference. Dual USB fast charger (3.1A): charge two devices simultaneously with intelligent power management for phones, tablets, and more. Builtin noise cancelling mic: clear, echo audio for safe and convenient hands calls. Digital voltage display: realtime monitoring of your car's battery status to support a safe driving experience. FM transmission range 87.5–108MHz: easy broadcasting of your music to the car stereo with a strong, stable signal. U disk and MP3 player support: play music directly from a USB drive up to 32GB — no Bluetooth required. Easy control knob: switch songs, adjust volume, answer or hang up calls, and change FM frequency with one control. Universal 12V/24V compatibility: suitable for cars, SUVs, trucks, and other vehicles. Use scenarios Daily commuting: stream your phone's music, take hands calls, and keep devices charged during short or long trips. Road trips and shared vehicles: use the USB drive MP3 player to play curated playlists, while the transmitter maintains charging and connectivity for all passengers. Fleet or work vehicles: compatible with 24V systems, monitor battery status in real time, and charge two devices at once during a workday.