MWEH HEH HEH! LOOK, BROTHER! WE ARE KEYCHAINS!
heh, that's nice, bro.
They are all 1.5" in size not including the keyring.
BONUS: If you order both UnderSwap Sans and UnderSwap Papyrus keychains in a combo, you get one of each as a button for free (sparkle or normal versions depending on which set you order). A $4 value, free~
UnderSwap Creator: popcornpr1nce.tumblr.com
Not officially licensed merchandise, but some really cool fan art!