Replacement Gels for S3/S4 Earbuds

[AC Question]

Hi all,pardon me if this has already been posted.... I am looking for a replacement pair of the earbud gels for my S3 Galaxy. I recently purchased a pair on Ebay, and they are too small. I have found a new seller on Amazon, but they are asking that I select a size (sm-lg). I didn't know these things had a size (lol), and don;t have a clue which to select. Please help! Thanks