MWEH HEH HEH! LOOK, BROTHER! WE ARE CHARMS!
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 charms in a combo, you get one of each as a button for free. A $4 value, free~
UnderSwap Creator: popcornpr1nce.tumblr.com
Not officially licensed merchandise, but some really cool fan art!