About two weeks ago I managed to pop the little rubber cover off one of my Apple in-ear headphones. It pinged off into the middle of the open railway crossings we have here in Australia, during a collision with one of my more indecisive fellow-pedestrians. These little rubber doobries have to fit your lughole snugly otherwise they sound shithouse.
I tried using the medium sized ones (the headphones come with three different sizes; my giant canals need the large size), but it was no good. I journeyed far and wide in search of replacement whatsits, but no-one makes them. Not even Apple.
In times of crisis I find it helps to turn to a higher power. Google found me an article where someone recommended the use of the foam sleeves for the Shure E2C in-ear headphones. These happen to be a perfect fit for the Apple ones.
Great! Only problem is that there are only two places in Australia that distribute them. One charges $35, with free shipping. The other charges $25, plus $7 shipping. The headphones themselves only cost me $60. Sod that. Ebay to the rescue: there's a company in America that sells them for $16 US (about $20), free shipping to Australia. Hooray for the Internet.
They arrived in less than a week, and they sound fantastic. They really improve the bass, and they're a lot more comfortable than the original rubber thingummies. If, anonymous Internet reader, you have a pair of the Apple in-ear headphones, get these foam sleeves (the same size as you use for the Apple ones should do).