There is wet perlite in the bottom bowl, then I drilled a bunch of pin holes in another bowl and placed that into the perlite bowl. I put a layer of tape around the two bowl lips to make a tight seal, then the eggs went in. So yes, the eggs just sat in a plastic bowl with nothing else in it. They only received humidity from the bowl below them. I'm sure there are easier ways to do it, but the egg crate I use for ball python eggs is too open for small leo eggs, so I made the "steamer".