I love this USB car charger too much it literally has everything I need in one small unit. So like I said this thing basically a Victorinox Swiss Army Pocket Knifefor you car. So what can this little guy do let's see:Dual USB charging ports(USB PowerIQ 5V/2.4A + 5V/1.5A)Bluetooth 4.2 ReceiverFM TransmitterAUX Line OutMP3 Player(Through The Non-PowerIQ USB Port)Companion Roav App(FM Frequency Modulation and Car Locator)Thats everything in this little car charger now let's talk about how it perform. Right out the box simple to use you get the SmartCharge F2 it self, Owner's Manual, and a Happy Card. When I first plugged it in I switched it to the right FM frequency that is perfectly displayed on the screen of the SmartCharge F2 and voice promoted saying "waiting to pair" and after I got my phone connected to the bluetooth SmartCharge F2 the device replied with a satisfying voice "successfully paired" and my music automatically started playing.Now comparing this to there older bluetooth receiver that Anker currently still sells Anker SoundSync Drive Bluetooth 4.0 Car Receiver, Wireless Phone Call & Music Streaming Car Kit with Built-in Mic, Music Streaming, Echo and Noise Reduction, Multi-Point Access, 3.5mm Aux Cable When I connect to this adapter I would have to guess what sound I just heard and assume I was connected with a little blue led indicator that would blink rapidly until my phone was connected and even when I had my phone connect it would show with a solid blue light and not play music automatically. Comparing the 2 devices I really love the improvements they made especially bluetooth connection are stronger and more reliable than ever, every time i leave my car weather it was on or had to turn on when I get there the blue tooth automatically connect to last devices and starts playing music all on its own.How good is the FM Transmitter?Well pretty good in my opinion with the testing I've done. On the package and in Anker's page they state you have a transmission distance of 2 m witch is 6 ft. I got around 10-12 ft. with my testing with clear audio still. Another incidences where I tried this out is on a family trip if you're using two cars and following the other car at a 2 car length distance from each other both cars can get the same FM station and simultaneously play out of the both cars making an ultimate surround sound.How's audio quality compared from AUX V.S. FM Transmitter?Well there is a difference right away if you switch from the two output sources witch both will transmit simultaneously out of the AUX out and FM out.FM out when you find a good station thats just static and you hear no other interferences from other radio stations you audio quality is how any other radio station would sound it has that radio like sound that you would get not that loud and not that much base comparing it to the AUX out, nothing can compare to a true line in connection to your speakers. But when you have AUX out and you have not music playing you hear straight static noise from the negative connection being exposed of the 3.5mm port not being fully covered even when you play music you will hear it in the background. Audio quality is best with AUX out and with a AUKEY Ground Loop Noise Isolator for Car Stereo Systems and Home Audio Systems, 3.5mm Audio Cable Included this little devices will cancel out all the static noise that you get with the SamartCharge F2 and you will have quiet and uninterrupted music listening.MP3 Player Does it Work?Yes the MP3 player does work but when I first had this it didn't work at all, had a hard time finding out why but here is the solution if your MP3 won't play music after you inserted your usb flash drive here is why. Make sure your USB drive is formatted properly to the file system FAT, FAT23, exFAT and that you music is no where but at the root of the USB drive. The reason why I couldn't get mine to work is because when I formatted this flash drive on my MacBook the default File System was "mac-os x journaled" Also you music file format has to be in .mp3 .wma .flac. wav. in order for the MP3 player to work properly. After you have everything all set on your USB drive just insert into the non PowerIQ USB port your music should start playing if not just press the middle button(phone icon) and your music should start playing. When your playing a song or skipping a song the displaying shows you what track number your on for a couple of seconds and then goes back to displaying the FM frequency that its on. Other than my little issues that I had everything work beautifully and I use the MP3 mostly everyday its like your own personal station when you don't wanna mess with your phone for music and you hate using the radio because of all of the commercials.Car Locater?When I first heard about this I thought it had to be a joke or something because you couldn't add a devices with GPS for less then $25 and I was right the only thing the car locater does with the SmartCharge F2 is nothing. The car locater relies truly on your phone the app and your phones GPS location witch you mark yourself. I think the only thing that the SmartCharge F2 does for any location finding is telling when it's connected and not connected and will give the last location when the SmartCharge F2 was last connected. Haven't used it much since you need to open the app whenever you want to use it. For the most part I just plug it in and play my music don't really have need to go into app not unless i'm change my FM frequency witch I haven't had to do and on the app you have can have 3 Preset FM station to switch back and fourth from. i'll have to do more testing on the car locater and will update my review when I can.