If you're talking about the hinge we call treat balls they are great. In my opinion a much better way of feeding a puppy or dog than out of a bowl as they actually have to work for their food. And it keeps them busy and quiet! Merc has a few different ones and he gets one each morning with his kibble for the day. It did take a while for him to work out that there was food involved. You might find you need to spend some time teaching him what to do - but worth it in the long run.
The one I've seen is a wooden box with 4 different doors to it, one you have to open like a musical box, one has to be slid, the other pawed so that it flips. etc £20.00 doesn't seem too bad if it occupies his brain for a while..