Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Is this compatible to use with an Otter Box case and Defender cover on the iPhone 4s?
Document: This product works great if you do not use a case on your phone. We use the otter box case on the iPhone which will not allow the phone to connect to the device. We just use this for the touch now.
Thought would be a great product. Only use I have with it is just as an iPhone Holder.Problems I faced:1. Shows not compatible error on the iPhone.2. Does not work with Speck Cover on the iPhone.3. The radio goes completely off after a while.Number 3 is the most annoying of my grievances. Thought would be great to hear music in my car from my iPhone.I set the radio and it plays well for a while.
I bought this specifically to use as a hands-free option with my GPS app so it would go through my van speakers and for use with music through the van speakers for my iphone 4s. It was very easy to put together out of the box without instructions. It fits VERY snuggly in my cigarette lighter and is not going to be removed very much because of that. The previous car mount I had (not same brand) broke quickly due to tranferring from one vehicle to the other.
This did not work with my Iphone 4. I read the instructions, did all the right things. But could not get to work with the Iphone. I plug the auxillary cable in with the IPad and it worked great. No static great.When I hooked up the Iphone it read on my phone "unit is not compatible with the Iphone"  Weird beings the box says it's made for the Iphone.Good Luck.
It works great with my iPod touch 2nd generation. However, it does not work at all with my iPhone 3GS nor my wife's iPhone 4S. The iPhones display a message that the device is not compatible with iPhone. Again, this item DOES NOT WORK WITH IPHONE 3gs or 4s. It does work with ipod touch 2nd generation. DO NOT BUY THIS FOR AN IPHONE!! !
Plug fit so tight it damaged my Truck's Cigarette lighter port trying to remove it.Back plate depth is too short to allow connecting iPhone 4s with case on.Cigarette plug has "Nub" that may not clear some ports. How does it function electronically?I have no idea, I couldn't get that far!
For the other devices that I've had, the iPhone would continue charging despite "not being compatible". This isn't the case with the GOGroove FlexSMART. It would cease to charge my phone, while still playing music from it (sometimes with an interruption when the message would pop up).
I bought this to use with my iphone 3G, it worked great for the first month or two. Now it will not do anything! I receive a message from my iphone saying it's not compatible.
At first I was thrilled to get my GOGroove Flexsmart transmitter. I wanted to use it with my IPhone 4s to listen to my music and also charge the phone. As far as the music part, I have no complaints, but the charger stopped working after a couple of days.If I go on any significant drives and need to charge my phone I have to get out my other charger.
I bought this for my ipod touch 4g but it is not compatible folks! This must be a typo on their site. It only works with the included cable (intended for non-dockable mp3 players), but that makes the dock useless - and I got mine cause I loved the idea of a dock. The arm was nice and stable - although the actual dock only works if you take of any case on your ipod. Customer service was incredibly good - personal responses and quick.
Answer: I stopped using it. I was very unhappy with this product and the way it plugged into the lighter port.