If anyone is interested, I accidently ordered two of these interfaces and am now trying to get rid of it. I have the Alpine IVA-w505 with the sound processer(PXA-H100) and the navigation. Without this interface you are unable to hear route commands from the navigation when you are on a different source other than just navigation. Example(Say you are listening to your ipod(a source) and also have a route in progress; without this interface you will not hear the voice part of the route, just a flash of the map). I am asking $70 plus $10 for shipping and handling on ebay just so I can at least get my money back but I will take a resonable offer. Raymond