Users love the overall power and setup of the Nuxaly, with the most complaints coming from the rare occurrence of a pairing issue. Built-in Display: Yes | USB Ports: 1 | USB Audio Playback: MP3 | Operating Voltage: 12V-24V The Hands Free Bluetooth Transmitter by LIHAN features a 3.1A and 1A input offering both 12v and 24v charging for both you and a passenger. This means that your mobile devices can be charged in a jiffy all while listening to your favorite music. Its wireless Bluetooth 4.0 connectivity also offers low power consumption with a 5 percent loss of battery to your device each hour. Like many transmitters on the list, it includes a microphone for hands-free calling. This product has been praised for its ease of use and adaptability. More critical reviews noted that the connectivity could sometimes be an issue. Built-in Display: No | USB Ports: 2 | USB Audio Playback: MP3, WMA | Operating Voltage: 12V-24V There are two USB output ports for charging phones, including a 2.0 smart port and a 3.0 Quick Charge port. There’s a super-bright 1.7-inch LCD screen that shows song and phone info but will also display the car battery level. There are three means of connecting audio here, too: your phone’s Bluetooth connection, a standard aux cable, and even the capability to read a microSD card. Unlike some of the lower end transmitters, it supports more lossless audio than MP3 including FLAC, and with support for A2DP and headset protocol, it’s the perfect phone accessory for cars that are lacking some modern AV. Built-in Display: Yes | USB Ports: 2 | USB Audio Playback: MP3, WMA | Operating Voltage: 12V-24V The transmitter has an easy-to-read display with intuitive buttons for adjusting frequency. It also comes with an extra USB port, so you can charge devices while driving. For best performance, we recommend using lower channels in the 80s and 90s. Built-in Display: No | USB Ports: 1 | USB Audio Playback: N/A | Operating Voltage: 12V-24V The Criacr FM transmitter also features a pair of USB charging ports to keep all your devices topped off, as well as a trio of multi-function buttons for hands-free calling and music controls. Perhaps the coolest feature, however, is the built-in LED lighting strip that can bet set to six available colors or cycle through them to provide some necessary flair to your car. Built-in Display: No | USB Ports: 2 | USB Audio Playback: MP3, WMA | Operating Voltage: 12V-24V

Connectivity

FM transmitters use audio jacks, USB, and Bluetooth to connect to phones. If you have a newer iPhone that doesn’t have an audio jack, make sure to get a transmitter that has a USB port or Bluetooth that’s compatible with your phone.

Hands-free calling

If you go with a Bluetooth transmitter that has a hands-free mode, you’ll be able to make and receive calls without taking your hands off the wheel. Transmitters with this feature are also capable of muting or pausing your music during a call and starting it back up again when you’re done.