GG game buttons

So I'm new to Busan, and I'm trying to find some GG buttons for gamer friends back home.  I don't know the Korean characters for it.   All I know is that gamers say "GG" when a game is over and there's a button you can push.  I figured these would be great souvenirs.  Any idea where to find them?  Or if they exist in Korea? Thanks for your help!