I have Phillips earbuds and the clear plastic part that covers the end got lost, how do i replace it?

I have the phillips earbuds that fit snug into your ear the clear plastic round part at the end of the earbuds fell off somewhere and I lost it. I asked my friend who had a pair if there was a replacement anywhere he said none that he knows of. I find it hard to believe they don't have any of those plastic round rings anywhere incase it falls off and you need to replace it. Does anyone know where I can find it? a href="http://i90.photobucket.com/albums/k268/tloutn/RW/thumb2.jpg" rel="nofollow"http://i90.photobucket.com/albums/k268/t…/a thats what they look like the clear plastic goes around them at the end.