http://www.boomerangtags.com has some tiny tags, and they still fit on the pertinent info too! Stainless Steel is what I get - have DEEP engraving so you don't have to ever worry about the engraving rubbing down where you can't read it. Order online and it's usually in your mailbox within 3 to 4 days (CA to KY anyway). They supply either an S hook or a split ring for you as well. Can't go wrong with Boomerang! I LOVE them, and their customer service people are wonderful!
