It's modified pvc, an air tight container, and rubber seals. It seriously cuts down on the mess. The babies still dribble water out of their beaks, but not too bad considering the alternatives. I got tired of swampy duckling brooders so this is what I came up with. I put a swim pan on top of a plastic tote lid in their brooder box once per day for a few hours.That i can honestly say i have not seen before? how does one make something like that?