They were advertised at Petco, but of course when I went there, they had never heard of them. I guess you have to order online, BUT, after I looked at the pic of the bowls again, I thought, hmmmmm it's just an insert inside the bowl. I improvised and so far it works. I simply put a plastice lid with three little holes in it, in Prince's water dish. The lid floats, he drinks slower, and most impotant...he DID NOT gag or spit up. I just saved 40 bucks!!!!!
You may have to trim the lid to fit the bowl, as I did. Just make sure there are no rough edges.
Try this before you spend your money...it will probably work for you.