RadTech 13-860 ProCable Shortz Dock Extender for iPhone, iPod and iPad - Black
I purchased this to use with a Lifeproof iPhone case.  Well, it plugs in fine with the case, but only worked once when I connected the Extender to my car's iPhone cable.  The next time I plugged it in, the car could not read the iPhone nor play any music from it.  Then I tried it on my iHome player and same result...no luck.  A waste of $20 in my case.