I have one, they are not all they are cracked up to be. I have yet to find one that doesn't slide down the dog if not perfectly balanced on both sides. Mine is actually a vest that has a backpack attachment -- what I did was put iron-on letters on the vest that say "Medical Alert Dog" so that I could further solialise Visa by bringing her into public. It's worked wonders, she's much better with people now. As far as the backpack part goes though, I think we've used it twice.