Functions: Receiver USB Mode: The usb mode does not need to use 3.5 audio cables. It can be directly plugged into the car usb interface and speaker usb interface, and can be used directly after pairing with the mobile phone. Note: The car usb interface and speaker usb interface must support usb audio output. Receiver AUX Mode: AUX Mode needs to connect one end of the 3.5 audio cable to the MSD-128 audio interface, and the other end to the car 3.5 audio interface and speaker 3.5 audio interface, and it can be used after pairing with the Bluetooth of the mobile phone. Bluetooth hands-free calling Built-in microphone, when the mobile phone is talking, you can make hands-free conversation through the microphone on MSD-128, which is very convenient to use in the car. Feature: Product Model: MSD-128 Bluetooth Version: V5.0+2.1EDR Bluetooth Distance: 10M Launch Distance <8M Working voltage: DC5V/2.1A(MAX) Power supply mode: USB power supply FM Frequency: 87.5MHZ/ 88.0MHZ/ 88.8MHZ Applicable Equipment: Speakers\ Car\Radio\Amplifier Package Included: 1x Bluetooth 5.0 Audio Receiver Adapter 1x 3.5mm Aux Cable 1x User Manual NO Retail Box. Packed Safely in Bubble Bag.