I bought this so i could plug headphones into my iphone 4 because my hard case's jack plug hole was too small.
this adapter Looks and feels even more high quality than sony or philips products, and doesnt effect the sound at all.
However the adaptor itself sticks out 3.7cm of the device (adaptor is 5cm long, but the jack is inside the device), so when you have headphones pluged into the adaptor its like having a walkie talky with a massive arial.