The 500XL Earbud Speakers were designed to be 500 times the size of normal iPod earbuds. I think they're just a conceptual product design by Fred & Friends, and thus don't exist in the real world yet (and may never). According to the company:
How great will these look on your desktop alongside your mp3 player or PC? 500XL includes a built-in amp and 3-way power - it runs on batteries; you can connect it to your PCâ€™s USB port with the supplied cord; or plug it into the wall with a generic power supply (not included). The stand-up, peggable clamshell packaging really makes a statement.
Now as a person with unusually large ears, I appreciate where they're going with this product. Unfortunately I just took some measurements and I'm going to have to hold out for the 750XL's to ensure a snug fit.