1. The default frequency band of W3 is 95.0MHZ, which can be used directly. If there is a lot of playback noise, it can be adjusted to other frequency bands. 2. When the radio of some models is turned on, the car's built-in usb interface be powered off. At this time, if the W3 is plugged into the built-in USB port, it cannot be used. In this case, you can plug the W3 into the usb of the lighter and car charger. The power supply is used on the interface (the output voltage of usb must be 5V). 3. W3 is used in some cars with usb interface, which may be too noisy or unusable. It is recommended to plug FM02 into the lighter car charger for use. 4. W3 has no automatic shutdown function, it is recommended to unplug it from the usb interface when not in use. 5. When the W3 cannot be searched in the Bluetooth settings of the mobile phone or cannot be paired after being searched and clicked, it is recommended that you clear the previously connected Bluetooth devices in the mobile phone, and then restart the mobile phone and try again. Specification: Product name: usb bluetooth FM transmitter Product model: W3 Bluetooth version: V5.3 Working voltage: 5V Effective probability: within 10 meters Audio output: FM transmitter Default frequency: 95.0MHZ Signal to noise ratio: equal 95db Answer the call: support Automatic return: support TF card:support AUX:support Power supply mode: usb power supply (5V) Usb interface: The usb interface is used for power supply. When using it, you can plug this product into the usb interface with an output voltage of 5V, for example: the car comes with a usb interface (5V), and the car charger interface (5V). Colour:Black Material:Plastic Package Contents: 1x Car Bluetooth Transmitter Receiver Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.