I actually used two identical bowls from my kitchen (haven't had a chance to buy/make some more yet). I want to get my bowls back eventually, so I didn't cut a hole, I propped each one up on a rock (they are both in the corner and cannot be moved so that they fall shut). If you want the ease of a butter bowl, without the look, you can cut a butter bowl to the size you need and hot glue/silicone rocks/pebbles/aquarium gravel to the top and sides. Another benefit to that is that it provides a rough surface for your snake during shedding.