She's got a plastic bottle with a bit of rope hanging out of the end.
You unscrew the bottom, put in a handful of dry food and screw it back up.
You then pull the rope up the bottle neck and a couple of bits of food come up with the knot at the bottom.
Steve's been doing it for her since we first gave it to her, but just now Mitzi did it herself and produced 2 bits of food... such a proud moment for both of us!
Mitzi is such a clever little pup!