i have one of these the cable fits perfectly into my audio jack on the top of my iphone 3gs but when i try to use it with my iphone 4s it fits very tight i almost have to jam it in and even then it doesnt feel like its all the way in there.. 1.) is the audio jack different in iphone 4s vs 3gs? 2.) does anyone have a reccomendation for a cassette adapter that fits perfectly?