We have the monkey backpack and also an elmo harness. I can't find the elmo one online, but it adjusts in size. It's got shoulder straps and velcros in the back. JJ can't get it off and that child can get out of darn near anything. I can fit Abby in the Elmo one and she is a big 5 year old. We got it at walmart.
This is what it looks like..
