Cosmos ® Black Cable 3 Ft USB Charge and Sync Data Cable + Dock Connector Extender Extension Cable for Ipod Touch Iphone 4 4s 3 3Gs + Cosmos Cable Tie
I bought this cable with the aim of using it as an extension for my car stereo iphone connection.  My iphone has a crack in the case near the dock connector so the newer connectors which don't have the push-in tabs tend to come loose.  This extension has the push-in tabs so it stays in place.  So far I've tested it in my car and also with a JBL On Stage II, both of which appear to confirm that power and audio are successfully passed through.  The USB cable is an added bonus and I'll be keeping that in my ba